DC Contactors


What Does "LVD" mean?

Low Voltage Disconnect

What is the maximum switched main contact voltage?

60VDC without Magnetic Blowouts/otherwise 96VDC. Type SW190B has double pole switching and can handle 120VDC

What are the main contact materials?

Presently about 10% Cadmium, the balance is Silver.

What are Magnetic Blowouts?

Rare Earth Magnets molded into the top cover which produce magnetic fields which act on the main contact arcing, thereby extinguishing the arc outwards. This is particularly true in the case of "Inductive Loads".

What is the Mechanical Life Expectancy of a contactor?

Based on a Mechanical Switching Formula located under the specifications section. Generally speaking, Mechanical Life of the contactor is based on type of load being switched along with the frequency of main contact switching-(duty cycle). For Severe Load Switching applications, the expected MTBF is between 1-1.5 million cycles. For Infrequent Light Load Switching-between 2.5-3 million operations.)

What is the worst type of load to switch?

Inductive Loads First, Capacitive Loads Second, Resistive Loads are the most forgiving loads to switch.

What is "HOT" versus "COLD" switching

Hot switching means closing the main contacts directly on the load, versus Cold switching means first closing the main contacts before switching the load.-The worst load switching is "HOT" switching of Inductive type loads).

What are ways in which to lower the power consumed by the operating coil?

Magnetic Latching/Coil Chopping, which are options for Albright DC Contactors)

What types of coil configurations do you have?

"CW"= Continuous Wound, rated for 100% Duty Cycle,
"Intermittently Wound"= 60% Duty Cycle,
"Prolonged Wound"= 80% Duty Cycle.
Continuously wound contactors are identified by CO written on the label

In a Static Power System, why do we need to size the coil voltage above the nominal rating, i.e. 24VDC/48VDC?

In a normal Static Power System, we need to take into account the "maximum battery equalization charge voltage" whereby if the nominal system DC voltage is at 24VDC, the maximum coil voltage will be around 30VDC CO. If the system nominal voltage is at 48VDC then we would size the maximum coil voltage at 60VDC CO. The reason for this is to alleviate any potential for premature coil thermal runaway.

What type of mounting brackets do you have?

The three types of mounting brackets are listed on Pages 2-3 of the Albright Technical Data Sheet.

What is the maximum current rating of the Albright DC contactor product line?

The maximum current rating is: 1800 amps, which is the SW1500 series.

Are Albright DC contactors UL rated?

Yes, there are two separate UL ratings for different applications, EV/MH-UL certification based on the UL583 Industrial Truck Standard, versus the UL Rating for Static Power Systems-UL1778, and most recently UL1801.

What is the coil ratings range for Albright DC contactors?

From 6VDC to 300 VDC in the standard Albright product line, i.e. SW80 through SW1500 series. In the Albright DC contactor range miniature series the coils may be wound from 6VDC to 120VDC.

Are spare parts available for the Albright DC contactors?

Yes, a separate Albright Spare Parts List is available.

What is the "end part number" on each Albright DC contactor label called?

This "suffix" number is called a "precise identity number" which identifies that specific Albright DC contactor number with a specific customer and contactor special features.

How can you tell if a contactor has magnetic blow outs?

This letter B in the model number such as SW180B indicates the presence of blow out magnets. In case of contactor SW200 however, the type SW200 means with blow outs and SW200A means without blow outs.

Are the main contacts polarities sensitive?

The contactors without blow out magnets can have any polarity on the main contacts. Types with blow out magnets need to be wired up with the higher potential at the terminal marked with a + sign on the top cover. This is necessary to ensure that the blow out magnets push the arc out of the contactor.


Controllers (General)


When trying to pick out a controller for my application, I see the desired model has some missing numbers. For example: 1204-2XX. What does the “XX” stand for?

The “XX” is a designation number that tells us what options are configured on a certain controller. Some of these options could be certain error detection configurations, software differences, or even an exclusive controller for a certain customer. We have some internal documentation which helps us figure out which controller would best fit your needs.

I have a motor controller that failed. It is a 1244-4401. I have an extra one on my shelf, but the model states it is a 1244-4403. It looks exactly the same as the old one. Will this work?

It is a tough question to answer just by looking at the model number of the controller without any supporting information. More than likely this will NOT be a “drop-in” replacement. Usually there is enough of a difference in the controllers, even though not externally apparent, that you will have some type of error occur. You will need to contact a Curtis representative and they will be able to research this and find out if it is possible to replace one controller with another.

I would like to have a manual for the Curtis controller I have. Where can I obtain this?

Most Curtis manuals can be found on our web page. The link is the following: http://www.curtisinst.com/index.cfm?fuseaction=cDatasheets.dspHome.

My controller has a problem and I need to fix it. I have an electrical background and would like to fix it myself. Can I have the schematics for this controller along with any replacement components I would need to fix it?

Unfortunately Curtis cannot provide this type of information and product. The schematics for our products are proprietary and cannot be distributed outside of Curtis. This also applies to the components that are found inside our products. Our authorized partner, Flight Systems Industrial Products (FSIP), does offer a repair service on selected controllers for a fee. You need to contact FSIP at 717-254-3747 and ask for the Repair Department.

I have a Curtis controller that failed. Where do I return this to receive a credit?

If you obtained this product through an official Curtis distributor, this should be returned back to the place of purchase. If you purchased this directly from Curtis, there are two locations in Curtis that handle product returns. If it were a motor controller, controller accessory, or a throttle, you would need to contact our California office at (925) 961-1088. Any other Curtis product would need to be handled through the New York office. Their number is (914) 666-2971.

Is it possible to have my controller customized to fit our needs?

This depends on many different factors. First we need to know the extent of customization. Next we need to know your projected volumes you plan on purchasing. After this information is obtained, it will be brought to project management’s attention and a decision will be made if it feasible. We will then contact you with applicable fees. An off-the-shelf- item is certainly more desirable to sell and would have a higher likelihood of inventory than a custom unit.

Can I obtain the internal controller components so I can fix it myself?

Due to liability and many other considerations, Curtis will not support external repair of our products. Repairs need to be performed at our authorized repair partner, Flight Systems Industrial Products (FSIP) at 717-254-3747.

What do I need to do to my controller to make my vehicle go faster?

This depends on what type of controller you have. It is advisable to keep the controller on the factory settings. Adjusting the current/voltage settings of the controller may result in vehicle component damage.

There are so many different controllers to choose from. Where do I start?

First you need to gather information about your application (motor type, motor current/voltage specifications, throttle type, type of application, and other components in your system that may interact with the controller). Once all of this information is gathered, you can call the Curtis Instruments Applications Engineering department at (914) 666-2971 for further advice.

How long in advance do I need to place an order for a controller?

Most of our products are “made-to-order”, which means we do not make the product until the order is placed. Our lead times vary due to the manufacturing location so please call the Curtis Customer Service team at (914) 666-2971 for exact lead times.

My controller states two voltages on its label. Does this mean it works within that range or only for the two voltages?

The controller works on any voltage within that nominal range.

Do Curtis Controllers have regenerative (regen) braking?

Permanent Magnet, SepEx and AC controllers do. The series wound models utilize Plug braking and Neutral braking (auto-plug). This slows the vehicle when changing direction or selecting neutral drive, but does not put energy back into the battery. For slow maneuvering operations it is very effective.

My controller has neutral braking, but sometimes it just coasts. Why?

Neutral braking (auto-plug) monitors the current flowing into the motor so that when the motor stops (near zero current) the direction contactors are released. If you have a poor floor surface contaminated with oil or grease and the braking force is set too high on the controller, then the tire will skid and the motor current will be zero which then turns off the contactors and the vehicle coasts. Floor conditions are important for safe operation of material handling equipment.

The neutral braking on my vehicle is too harsh even when set to a minimum level. What can I do?

Certain motor and gearbox configurations can cause this condition. It is possible to fit an Albright armature field weakening contactor that reduces the braking force when neutral is selected. Contact your local Curtis office for assistance.

What is the advantage of using a microprocessor based controller?

The microprocessor based controllers allow the OEM to adjust many control parameters using a 1311 programmer, so that superior vehicle performance can be achieved. In addition to this the microprocessor based models record any intermittent fault or operator errors which can be recovered by a service engineer also using the 1311 programmer. This greatly reduces any downtime due to fast vehicle analysis and speedy rectification.

Besides the motor controller what other products do I need for my EV?

You will need connectors for the battery leads and controller, throttle unit, contactors, battery discharge indicator, battery charger all of which Curtis can supply. For many OEM’s we even build all of this into one kit with one part number, making life easier for you the customer.

What size of heat-sink do I require?

This is difficult to answer as many conditions effect the heat generation and transfer process. The controllers are rated for 2 minutes at full current based on the conditions specified in the relevant manual. Aluminum plate of 6-10mm is often used. Start with the largest area possible and run tests to ensure the maximum operating temperature of the controller 85oC is not exceeded. Thermal transfer compound and electric fans may be used if the controller is used in a confined space or worked very hard.

Can I connect two controllers in parallel to get more power?

No, the controllers regulate the power using a Pulse Width Modulation (PWM) technique. The power that flows from the controller is in the form of a square wave. It is not possible to synchronize the square wave PWM from two controllers. Contact your local office for high power controllers.

Can one controller drive more than motor?

In most cases yes. The controller can either be switched to a different motor via contactors if the motors are used at different times or two motors may be connected in series or parallel. AC induction motors cannot be connected in parallel or series and separate controllers should be used. The controls can be connected in parallel or via CANbus.

Are the controllers UL approved?

Yes, Curtis controllers are approved and the Underwriters Laboratory file is UL?????

Are the controllers CE marked?

No, Curtis controllers are not CE marked as they are not a self contained system. EMC susceptibility and emissions are highly variable depending on the exact layout of connecting wires and motor types. It would therefore be incorrect to CE mark a controller and assume that the complete operational system would meet CE requirements. Curtis does however ensure that the controller not only meets but exceeds the CE requirements on an approved vehicle simulator.

Is there an on-charge interlock available to prevent the vehicle being driven away while on charge?

This is really only applicable to vehicles that have an on-board charger. Our Permanent magnet controllers have an inhibit connection that connects to on-board chargers such as the Curtis 1600 series and disables the controller while a mains input is present. With AC controllers this function can be enabled using the Vehicle Control Language (VCL). For other controllers either a relay interface or a 1310 vehicle system controller may be used.

What types of vehicle use Curtis Controllers?

Anything with battery supplies in the 12-144V range. The list is practically endless but here are a few; Mining locomotives, counterbalance trucks, Arial platforms, golf carts, mobility scooters, electric dragsters, municipal road vehicles, aircraft tow tractors, helicopter movers, stacker trucks, floor sweepers, pipe inspection vehicles, pedestrian tugs, cargo handlers, bicycles, neighborhood electric vehicles, compactors, pallet trucks, fairground rides, river boats……


SepEx Controllers


I am not familiar with SepEx, what can you tell me about it?

SepEx or Separately Excited DC motor belongs to the family of the wound field DC motors including; Series, Shunt, and Compound. It is a 4 terminal motor where the armature (A1 and A2) and field windings (S1 or F1 and S2 or F2), are brought out the like a Series motor. But unlike a Series motor, a SepEx motor field is wound with finer gauge wire of many turns, and has to be independently driven by a SepEx motor speed controller. Since all Curtis SepEx controllers offer full bridge control of the motor field, this will make changing in direction of travel quiet and seamless without the use of direction contactors.

What are some of the benefits for choosing a SepEx controller?

The benefits include smooth response at any speed, increase usable battery energy per battery charge, extend life of motor by reducing brush wear, reduce motor loss, and small package size. In addition, it is easy to install and service is simple.

What is Multimode?

Multimode is a feature commonly available in all SepEx controllers to allow user to instantly change an entire set of parameters, such as speed, acceleration, deceleration and current limits to preset levels for up to four different vehicle operating modes.

Can Series motors be converted to SepEx motors?

Yes, generally but require lots of time and effort. The large gauge wire, low turns field winding can be replaced by a small gauge wire, high turns field winding. When doing so, the field must be designed to draw the required current but not higher than the controller’s maximum field current at low battery, when the motor is hot.

How do losses compare between Series motors and SepEx motors?

Losses in the field are a function of the square of the current (I2R). Typical losses in a Series motor field might be 0.020 ohms x 400 amps squared = 3200 watts. Typical losses in a SepEx motor field might be 0.32 ohms x 50 amps squared = 800 watts. Similarly we can expect fewer losses in a SepEx controller compared to a Series controller.

Does the higher inductance of the SepEx motor field cause any problems?

The higher inductances of the field are not a problem for Curtis controllers. The increased inductance does slow the transition between forward and reverse, but this can be tuned by changing the parameter settings in a SepEx controller.

I heard that Series motors produce more torque than SepEx motors.

This is not true when an electronic motor controller is used. A motor controller will limit the current to a Series motor, effectively limiting its torque to the controller’s maximum current rating. A Series motor will only provide more torque than an equivalent SepEx motor if the Series motor is connected directly to a battery without any current limiting. In this case, the stalled motor current would be very high due to zero armature back EMF. However, once the motor got spinning, the torque would rapidly decrease.

What is the difference between neutral braking and regenerative braking?

Neutral braking simulates the feel of “compression braking” that occurs when the operator led off the accelerator pedal of an internal combustion engine car. On the other hand, regenerative braking occurs when current generated by the motor during braking is allowed to flow back into the batteries.

What does it mean when a SepEx controller is available with CAN?

A few SepEx controllers are available with CAN (Controller Area Network) option to accommodate CAN-based truck application. In such application, a CAN interface and its simple wiring harness are used to replace a more complex wiring harness between a tiller head or “man-up” platform and Curtis controller. This means all normal input signals received by the motor controller may be replaced by CAN messages, thus freeing up multiple inputs and outputs to be wired to a variety of customer-specific needs.

Can a SepEx controller’s performance be adjusted and what equipment do I need?

All Curtis SepEx controllers are fully programmable through a Curtis 1311 handheld programmer allowing the operator to change the controller’s parameter settings. Use of the programmer also provides diagnostic and quick test capability. The programmer is powered by the controller, which makes it very portable and convenient to use anywhere.

Are there any SepEx controllers specifically designed for pump application?

There are a few controllers (i.e. 1254 & 1297) designed to provide finer control for pump motor than traction motor controllers with special features tailored for lifting and lowering operations.

When the vehicle is on a ramp or a hill, the vehicle tends to roll backward before the brake engaged. How can the rolling be prevented?

The parameter Restraint determines how strongly the controller will attempt to limit the vehicle speed to the existing throttle setting. This feature will help hold the vehicle on a ramp and the mechanical or electromagnetic brake has not engaged.

My controller doesn’t work. What is wrong with it?

Look for the LED flash code on top of the controller. If it is not flashing then you probably have lost the power to the control system. In which case check for charged batteries, good connections and intact fuses. If the flash code is one single flash then the controller is operational but has yet to receive a full set of drive signals. i.e. Key switch, interlock, direction and throttle. A different flash code indicates a system fault which may or may not be controller related. This flash code should be checked against the diagnostics table in the controller manual which may be downloaded from the Curtis website.

The main contactor pulls in then drops out again and then the controller shows a contactor did not close (Contactor DNC) fault. What is wrong?

As part of the controller initialization routine the voltage on the B+ supply to the controller is tested to ensure that the contactor is not welded and to ensure the contactor has closed. If the voltage does not rise to a preset level within a certain time then the contactor is released. The cause is likely to be very low battery voltage or contaminated or damaged contactor tips. Never force a main contactor closed as this may lead to controller damage and personal injury.

My controller is showing welded contactor even though the contactor is open. Why is that?

The controller determines that the contactor is welded by measuring the voltage on the B+ terminal with the contactor coil switched off. Before doing this test the controller capacitor bank connected to B+ is discharged by energizing the motor armature. If the armature has an open circuit winding then the capacitor bank remains charged and the controller assumes that the contactor is welded. Alternatively there is an electrical short circuit on the system where the main contactor is bypassed.

Why do the brushes on my SepEx motor wear down so quickly?

SepEx controllers are able to regenerate the braking energy by using the motor as a generator. However if the regen braking current is set too high then the commutator can suffer from flashover and an electric arc is set-up which can vaporize the carbon brushes. Regeneration is more likely to induce this due to the raised voltage across the motor. The regen current should be reduced to a lower level.

Why does my controller fault code show Contactor Missing yet the contactor is there?

If the main contactor coil is OK and the wiring is intact, check that the auxiliary contactor driver is turned off if unused and also the electromagnetic brake driver is turned off if unused. Both of these are tested as part of the contactor check routine.

Why does my Curtis controller run so much cooler than other manufacturer’s products?

Many people can produce a controller, sometimes at a lower cost, but Curtis has many years experience and invest a great deal of effort in fine tuning the power switching circuits. This understanding of the fundamental intricacies of power switching PWM ensures greater reliability due to lower component temperatures, and a lower system cost due to much reduced heatsink and cooling fan requirements.

Can I run a dual drive system with SepEx?

Yes, a pair of SepEx controllers with integral CANbus interface can be used with the Curtis 1310 vehicle system controller. The 1310 vehicle system controller, reading the vehicle speed, steering angle and mast height can calculate the control vectors which are then sent via the CANbus to the controllers.

Is the Regen braking only effective at high speed?

No the Curtis controller can regen current into the battery almost to zero vehicle speed. This is enabled by using the motor Armature windings as a charge pump circuit. At low speeds the Armature is shorted allowing the current to rise. When Armature circuit short is released the high voltage generated from the collapsing magnetic field allows the current to flow into the battery.

Is the SepEx system closed loop?

Not entirely in the fact that there is no speed encoder feeding information back into the controller. However the voltage applied and the current flowing into the field and armature circuits is measured using high precision Hall Effect sensors and used by the motor drive algorithms to ensure the highest possible performance.

What voltages can you run the SepEx controllers at?

The smallest SepEx controller is the 24V 200Amp model 1243 and the largest is the 80V 600Amp model 1244. Two of these in a dual drive system would give you 80V @ 1200 Amps or 96kW. That’s enough for the majority of applications!

Can I get controller status information out to a dashboard?

Yes you can, either by using an 840 Spyglass display which connects to the serial interface or via the CAN bus, or by hard wiring the fault code LED drivers to a dashboard indicator lamp.

What causes a controller to fail?

In the vast majority of cases the controller will detect a fault and shutdown safely to protect itself and the user. A catastrophic motor failure such as a burst Armature or the brush gear working loose will cause an Armature to Field short and destroy the controller. With good maintenance of the vehicle the controller will outlive the application.


AC Controllers


Can I use an industrial motor with the Curtis AC controller?

No, the industrial motors are wound for high voltage operation. The AC induction motor controllers designed for material handling applications are wound for low voltage, typically in the 15 – 50 V rms range. We work closely with motor suppliers and can help you to locate a suitable motor.

Do I need an inverter and a controller?

No, the Curtis AC controller converts the DC battery power into low voltage 3 phase AC power while simultaneously controlling motor torque speed and direction. As an added bonus you also dispense with costly direction contactors and additional power wiring.

What type of encoder do I need?

You need a 2 channel quadrature encoder which provides motor speed and direction feedback for the controller. This ensures the best efficiency from the control system which in turn gives cooler running and longer battery life. Many of the AC induction motors now incorporate and integral bearing encoder.

Is the AC system very powerful when starting?

Yes, the Curtis vector controlled algorithms provide high torque start up conditions with both 4 and 6 pole 3 phase induction motors. In many applications the performance exceeds conventional DC systems.

What is VCL used for?

VCL is the unique Curtis Vehicle Control language. The 1234, 1236, 1238 controllers and the 1310 Vehicle System Controller have a PLC type facility that allows you, the customer, to download your own specific code into the controller. By using this you can rid yourself of the relay interface logic of times past. You can also drive your entire truck through the VCL and CANbus system.

What is the maximum speed for the motor?

The Curtis AC controllers can output a sine wave from 0 – 200Hz and drive 2, 4 or 6 pole motors. This equates to a theoretical maximum speed of 12000 rpm for 2 poles, 6000 rpm for 4 poles and 3000 rpm for 6 poles.

What are the benefits of using AC?

With the Curtis AC + VCL controllers you have an ageless system because as your market requirements change then so can your VCL. Never again do you have to throw out the entire control system just to add a new feature. On the motor side, the AC solution can provide sealed motors with no brushes to maintain. AC also provides closed loop control which means no over-speeding and burst armatures. Adding to this fewer contactors means that both reliability and performance is increased for your product.


Mobility Aid


How do you properly set up and tune controller?

Please refer to section 4 of the 1228 manual for proper set up. It is critical that the Motor R parameter be set correctly. It is a relatively easy procedure to initially set up.

What is IR Comp?

IR Compensation is a method by which the controller maintains a constant vehicle speed despite changes in motor loading, i.e. ramps, curbs, inclines, etc

Mode 1 options are not affected by parameters. Is something wrong?

Default wiring is set to Mode 2 operation. The Mode switch must be connected to 24 V and engage for Mode 1 operation.

I keep getting HPD error. My wig-wag throttle is set to the middle position, is there something I can do?

The most likely culprit is that the potentiometer resistance has drifted over time from its initial setup. The controller has the ability to compensate for this resistance drift by increasing the throttle dead band parameter.

What is the difference between 1228-27Xxand 1228-29XX?

Model 1228-29XX is the latest generation 1228 controller. Model 1228-29XX has the capability to sustain 110 A for a longer period of time.

What is the difference between your connector systems?

The 1288 family is provided in three different iterations of connectors: the Curtis Connector System, the Beau connector system, and the Anderson connector system. The Curtis Connector System offers the most integrated package of the three. However, utilizing three different connector systems allows customers the flexibility to integrate the 1288 into their current design.

Can we use a XLR connector for a battery charger?

Yes, Curtis Instruments sells a conversion cable to connect to the Curtis Conexall.

Is the joystick replaceable?

No the joystick is not replaceable, but can be replaced at an authorized Curtis service center.

Can the 1288 brake faults be disabled for other applications other than DME?

Yes, the brake function can be disabled by using 200 Ohms resistors on the brake output.

What is the current rating of the Controller (short time and continuous)?

The Controller can provide 100 ampere for a short time and 35 ampere continuously for each drive motor. For more details, consult the user manual of the controller.

Which third party infrared equipment can be operated through the MC-2 System?

About 90% of all infrared commands can be learned by the LCD Infrared Module.

How many seat motors can be connected to the MC-2 System?

Up to two motors can be connected directly to a Controller with Actuators. More motors can be used when one or more Seat modules are connected to the MC-2 System. Each Seat module offers 5 additional channels.

What alternative input module does the MC-2 System offer, other than the Handcontrol?

1-,2-,3- and 5-Switch Tash, Sip & Puff, and Standalone Joystick.

Where can the charger be connected to the MC-2 System?

Every free bus connector in the MC-2 System can be used to connect the charger (e.g. the bus connector on the Hand control).

How many modules can be connected together in an MC-2 System?

Up to ten modules can be connected together like a network in the MC-2 System. However some modules can only be used once per system (e.g. Controller or Hand control). Multiple Seat modules and ECU Modules can be part of the system. For more details, consult the user manual.

What do I have to do, if I have mounted a new MC-2 system the first time on a new chair?

In the MC-2 OEM Manual is an Initial checklist chapter. Follow the instructions given there.

I would like to have the manual for the MC-2 system. Where can I obtain this?

The manual can be found on our web page. The link is the following: http://www.curtisinst.com/index.cfm?fuseaction=cDatasheets.dspListDS&CatID=1.

I have an LCD with a 5 switch input on the chair. Where do I have to adjust the drive performance?

If you connect the handheld programmer to the system, you will find under Program the menu entry Specialty Drive. You have to adjust the Specialty Drive. The MC-2 system distinguishes between three different input device families: Hand control, Specialty Input Devices (all switched Input) and Attendant Control. Each of this input device has its set of drive modes (Hand control Drive, Specialty Drive and Attendant Drive).

How do I have to program the system to be able to use a switch input?

For Switch Input, the LCD Display is required. Please check chapter 1712-6010 LCD Display in the OEM Manual.

Can I use a normally open contact for the MFS (Multi Function Switch)?

No. The MFS has to be wired as described in the Manual under Wiring the 1712-6010 LCD Display. With the two resistors wired with the switch, a proper monitoring of the MFS is possible (detection of loss, short and cut cable).


Battery Chargers


What is Opportunity Charging

Opportunity charging refers to the ability to restore ampere-hours to the battery whenever the vehicle operator has the opportunity. Whenever the vehicle is idle as part of the operator’s routine, he/she can connect the charger and add energy to the battery.

What do the LED’s tell me about the charger?

Two LEDs (one yellow and one green) inform the user of charge status: Yellow On – AC Power present Green On – Charge Complete Green Blinking – Charging Yellow & Green On – Standby Mode Yellow & Green Blinking – No battery or reverse polarity

Do I need to set a timer on the charger?

There is no need to set a timer for basic charging. Unlike many Ferro-resonant chargers, Curtis chargers will automatically detect when charge is complete and the charger will shut itself off. If desired, specific charge cycle times can be programmed into Curtis chargers.

Can I turn off the fan?

Yes, the charger can be programmed so that the fan is on at full speed when the charger is charging or it can be programmed so the speed of the fan is proportional to the temperature of the charger. This feature is called fan modulation.

What is multimode charging?

Multistage charging ensures batteries receive optimum charging, but with minimal wear and tear, regulating the voltage and current delivered to the batteries in three automatic stages:
- Bulk: Replaces 70-80% of the battery’s state of charge at the fastest possible rate.
- Absorption: Replenishes the remaining 20-30% of charge, bringing the battery to a full charge at a slow, safe rate.
- Float: Voltage is reduced and held constant in order to prevent damage and keep batteries at a full charge.

Why shouldn't I just use a Ferro-resonant charger?

Ferro-resonant chargers tend to either undercharge or overcharge your batteries. Basic chargers apply a set charge rate and then shut off with a timer. Batteries that are only partially discharged will receive the same timed charge and your batteries may overcharge which will cause them to overheat and could damage your batteries which will reduce your batteries life. Ferro-resonant chargers also don't have protection features to prevent overcharge such as temperature and voltage drop sensors. Also if there is a power interruption during charge the timer will start over and could result in overcharging your batteries.

What is the warranty for Curtis battery chargers?

Two years from the time of delivery.

Ferro-resonant battery chargers are big, heavy, and inefficient.

We abandoned the “old method” years ago due to technological advancements. We only manufacture solid state, high frequency units that are compact, light weight and far more efficient. This result in much better charging technology that makes the batteries last longer.

The price of metal keeps going up, causing unanticipated product price increases.

Using a high frequency, solid state design gives us a more stable cost platform. We are able to do a better job of controlling costs while providing expanded features.

In some of our applications, certifications are important to us. What do we do?

Depending on your application, we have a product for you. The ProTech-C, for example, is certified to UL1564, 3rd edition which is the most recent UL standard available for Industrial charger applications as of this writing. We also carry CE marks so you know we are compatible in multiple global markets.

The charger I have now seems to overcharge or undercharge my batteries.

We work closely with the major battery manufacturers to identify their charging requirements and make sure that we put out a proper charge curve to get the job done as expertly as possible. The ProTech-C (as well as other products that we make) can handle multiple battery types thus helping to “future proof” you against changing battery types.

As an OEM I have some applications that require an onboard charger, a portable charger, 120VAC systems and 220VAC systems for overseas applications. I also use different batteries depending on the application. How can I avoid stocking so many different chargers?

Through the ProTech-C’s innovative product design, we can convert the onboard charger to a portable charger and the unit automatically ranges across the spectrum of AC input voltages. We also work with all 3 major battery types. This greatly expands inventory flexibility and reduces skus. The “onboard” unit slips quickly into the carry case assembly and converts to a portable unit. Since we use connectors on inputs and outputs, our cable assemblies are customized for the application. It really couldn’t be any simpler (or quicker).


Battery Discharge Indicator


I just installed a new battery gage. The gage indicates “full battery”, but I know that this battery has been in use for several hours, and the battery capacity is much lower than “full”. Why does the gage show full?

A new gage installed for the first time will read “Full” (the final step of our Quality Control procedure is to reset the gage to full). As vehicle use begins, the energy from the battery is used, and the gage will move quickly through its steps to “catch up” with the true battery capacity. The process of the gage dropping from full to empty will take at least ½ hour on a loaded battery.

How does the instrument measure the discharge of the battery?

The instrument measures the Voltage under Load below a ‘reference”. As the vehicle is operated, the load on the battery causes the voltage to drop below this reference level. The gage will accumulate the time the voltage is below the reference. When the voltage is below the reference for a sufficient period of time, the gage will reset its timer, lower its reference, and indicate a lower state-of-charge. This process is repeated until the gage reaches “empty”. If the load is removed from the battery, the voltage will rise above the reference, the timer will stop, and the gage will continue to indicate the current state-of-charge. This technique of voltage-time integration to calculate the battery state-of-charge is far more accurate than using a simple voltmeter.

Why is it important that the wire from “Battery Plus” connects to the first positive vehicle connection (before all switches and fuses), and the “Battery Minus” wire connects to the first negative vehicle connection?

Every wire has a resistance, which will produce an additional voltage drop when there is a load on the battery. The intent is for the instrument to measure the drop in voltage (under load) of the battery. If there is an additional resistance (extra wire, key switch, etc) that causes an additional drop in voltage, the instrument will behave as if the battery voltage is dropping lower than it really is, and the gage will show “empty” before the battery is “empty” Voltage under load measured at the battery, should be within 1% of the voltage at the instrument terminals B+ and B-". Example: a load on a 24 volt battery causes a voltage reading of 22.6 volts when measured at the Battery Terminals. The same load, when measured at the B+ and B- terminals of the instrument, is 22.2 volts. (.4 volt difference. .4 divided by 22.6 = approx. 2 %. This is not an acceptable installation.

Will Curtis BDIs work on Sealed Lead-Acid Batteries?

Yes, if the Discharge Setting is correct. Although each manufacturer’s sealed battery may have its own unique characteristics, we have found that the setting “R” (which has an “empty” voltage under load value of 1.86 volts per cell) is appropriate for most sealed (VRLA- valve regulated lead acid-) applications. Curtis Model 803 has a wide range of adjustment, and is therefore recommended for sealed (VRLA –valve regulated lead acid-) batteries.

I have a Curtis 802 (or 803) installed, and it always reads “Full”? What is wrong?

Model 802 is “Dual Voltage” gauge. Your gauge may be connected to the wrong “Battery +” terminal. The 2436 model has the ability to measure a 24 volt battery OR a 36 volt battery, depending on the wiring. There are 2 terminals on the back of model 802: Battery HI (Pin1), and Battery + LOW (Pin5). If the gauge is installed on a 24 volt battery, then the Battery + “Low” terminal is connected (because 24 is ‘lower’ than 36). In this case, no connection is made to Battery + “High” --- If the instrument is measuring a 36 volt battery, then the Battery + High is used, and no connection is made to Battery + Low.

I have a Model 802 BDI (or 803) installed and it goes rapidly down to Empty and stays there. What is wrong?

For a 2436 Model that is being installed on a 36 volt battery, you must connect “Battery + High” (because 36 is ‘higher’ than 24) and leave “Battery + Low” unconnected.

Resetting the Gage to Full: What is the difference between OCR, HVR, and CTR?

OCR (Open Circuit Reset) -- This method of resetting the gage to full is used in applications where the battery is charged while disconnected from the gage. (Typical of forklifts). When the battery is disconnected, charged, and then reconnected, Curtis models with OCR will reset to full (‘jump’ to full), IF the voltage is greater than the OCR reset level voltage.

- Example: 900R24BN. The “B” in this model means that the open circuit reset level is 2.09 Volts per cell. (12 cells x 2.09 = 25.1 volts); if the gage sees a voltage higher than (approximately) 25.1 volts per cell, it will reset to Full.

HVR (High Voltage Reset) – This method of resetting the battery to full is used in applications where the battery is charged while connected to the gage (typical of golf cars and scissors lifts). The gage will reset to full when the charging voltage exceeds the HVR reset level, and maintains it for 6 continuous minutes.

- Example: 900R36HG: the H reset level is 2.35 volts per cell (18 cells x 2.35 = 42.3 volts) When the charging voltage exceeds (approx.) 42.3 volts and stays above this level for 6 continuous minutes, the gage will reset to Full. (Note: 900RBN models include both HVR and OCR)

CTR (Charge Tracking Reset). This method of resetting to full is useful in applications where the battery is partially charged before being put back into service. Models with this feature will track and display state of charge incrementally when the battery is being charged. Model 803 and 3000 series enGage models have CTR.

What is the difference between a Curtis BDI and a Voltmeter?

A voltmeter will show the instantaneous voltage. When a load is put on the battery (such as lifting a pallet of 180 cases of beer), the voltage display will fall to a low reading, and then go back up when the lift has been completed. With a voltmeter, it is difficult to tell the battery state-of-charge. The Curtis BDI uses an algorithm that monitors the battery when it is under load. The battery state-of-charge is displayed in a Full to Empty display (like an automobile fuel gage).

Will Model 906 12volt works with a 12 volt Nickel-Cadmium (NiCad) battery?

Probably not. The voltage response for NiCad batteries is very “flat” which can make it difficult to track. However, if data on a specific battery model is available, we can evaluate if we have an appropriate BDI for a particular application. Please check with Curtis Applications Engineering Dept. The Curtis 933/3 (or 803) shows Empty too soon. I only get 2-3 hours of work from the battery and the Specific Gravity is 1200. I’ve double-checked the installation of the gage, and it is correct. If a battery is being discharged at a high rate, the SG that corresponds to 80% discharged will be significantly higher than if the battery is being discharged at a lower rate. For a certain battery type, a 600 amp-hour battery with a constant load of 100 amps is being discharged at the 6-hour rate. The SG at 80% discharge for this battery is 1.180. If the truck using this battery did very heavy work (an average load of 222 amps (2-hour rate), the battery is no longer a 600 amp hour battery in terms of useable capacity. In this instance, the useable capacity of the battery (at this high discharge rate) is 444 Ampere hours. The 80% Specific Gravity corresponding to 80% discharge is approximately 1.220.


Counting and Timing


What is the difference between a model 700 and a model 701 hour meter?

The model 700 hour meter will turn on its display and begin to accumulate time when power is applied to its V+ and V- pins. When power is removed the display will blank out. The model 701 hour meter will turn on its display when power is applied to its V+ and V- pins. However, it will not accumulate time until power is applied to it Input pin. In this manner, the model 701 hour meter can have its display on continuously for viewing at any time without accumulating time.

Which is the most popular hour meter case style? Which is the most popular counter case style?

The “Q” case style is the most popular hour meter case style. (Please show samples of case styles). The “D” case style is the most popular counter case style.

What happens when the 700/701 hour meter display is filled up? That is, after 99999.9 hours have elapsed? And if it operates 24 hours a day, how many years does it take to reach this point?

After 99999.9 hours the hour meter will roll over to 0.0 hours. Operating 24 hours a day it takes these six digit hour meter 11.45 years to reach this point.

Do I have to wait 0.1 hour (6 minutes) for the hour meter to increment to know if the 700/701 hour meter is accumulating time?

No, the hour glass icon on the left-hand of the display will flash on for 3 seconds and off for one while the hour meter is accumulating time.

Years ago I had seen LCD’s that turn black when left out in the sun. Does the 700/701 hour meter need to be shielded from the full sun?

The LCD’s which turned black in the sun were not able to withstand a high ambient temperature. The LCD for the 700/701 hour meter is designed to operate up to 85° C (185° F). The hour meter can operate in full sun without requiring a shield.

I want to replace an electromechanical hour meter. Does Curtis make an hour meter that I can set to the number of hours that is displayed on my old unit so that I can continue to keep track of the total hours on my machinery?

A stand-alone settable hour meter is not offered by Curtis. A settable hour meter is offered within the enGage II and enGage III units in combination with another gage.

How can I find out which Curtis hour meters and counters are UL recognized?

The Curtis components which are UL recognized are listed in the UL website, www.ul.com. Look in their Online Certification Directory and search for UL File Number E45175, Time Indicating and Recording Appliances – Components or AU1841 Industrial Truck Accessories, Battery Powered -- Components

Does Curtis offer replacements for the FUJI coulometer that have been obsoleted?

Curtis has been supplying components to manufactures who are supplying replacements to these coulometer. Please contact the Curtis Applications Engineering department for the current list of these vendors.

In which 5mm case style is backlighting available for the 700/701 hour meters?

Backlighting is only available for the 7mm encased units. These 7mm backlit units are available in a 48 mm square “S” case and a 2 inch round “R” case style. Backlit 5 mm hour meter modules (without a case) are available for use in designs that provide their own mechanical protection.

Does the display on the model 703 pulse counter increment on the high-going edge or on the low-going edge of the pulse?

This display will increment on the low-going (trailing) edge of the pulse.

Do you have an hour meter that can operate at 480 VAC?

With an external diode and dropping resistor, the model 700/701 hour meters can operate at this voltage. Contact a Curtis Applications Engineer for more details.

How does a Curtis model 700/701 hour meter differ from most other LCD hour meters in the market?

Most other LCD hour meters in the market use a battery to power the LCD and to store the accumulated time. This battery is likely to wear out, especially at extreme high or low temperatures. The Curtis hour meter uses does not use a battery to retain the accumulated time. Rather, it detects when power has been removed and stores the accumulated time in a non-volatile memory. This memory will store the accumulated time, without power, for up to 25 years.