Baker forklift + Suzuki Swift + Geo Metro = Project ForkenSwiftProject ForkenSwift - Electric car conversion on a beer budget

GE EV-1 DC motor controller

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GE EV-1 DC motor controller

The EV-1 SCR (silicon controlled resistance) type of controller actually has decent features: including adjustable acceleration (via a potentiometer), automatic motor field weakening (for faster motor speed under light load), and a "wide open" power bypass that effectively connects the batteries directly to the motor when high current is demanded. (Think: turbo!)

It's a reliable controller that was fairly widely used in industry and in some earlier EV conversions.

- examples

1987 Suzuki Forsa - 120 volts

1981 Jet Electra Van 600 - 102 volts

1975 Triumph Spitfire - 108 volts

But it's old technology, and one thing I learned from the EVDL is that it isn't ideal for use with a small battery pack (relative to forklift packs weighing several thousand pounds). The explanation is a little over my head, but has to do with the fact that the EV-1 lacks the capa citors that a more modern PWM style controller has. Lacking capacitance, current drawn via the EV-1 tends to be harder on a small pack, leading to lower efficiency (somewhat reduced range and battery life).

View all ForkenSwift galleries > DC motor controller ...

Curtis 1204-412 motor controller
That green box is the controller that's in the car now: a rebuilt Curtis 36-48 volt 400 amp DC motor controller original...
GE EV-1 control panel
Here's the brains of the forklift.

This control panel includes all the circuitry, fuses and contactors (big relays)...
GE EV-1 DC motor controller
The EV-1 SCR (silicon controlled resistance) type of controller actually has decent features: including adjustable accel...
The GE EV-1 controller on the "test bench"
We knew that the EV-1 worked: we had dropped 3 marine batteries in the Baker forklift and moved it under its own power f...
GE EV-1 controller in action (light test)
For testing, instead of controlling a DC motor, the EV-1 was hooked up to one of the 36 volt spotlights from the forklif...
Curtis 1204-410 36-48 volt 225 amp Club Car golf cart controller
Even after getting the EV-1 to work, we decided a "plug and play" golf cart controller would be easier for testing/devel...
Finned aluminum heat sink
(Inset: controller mounted on the heatsink)

Controllers can get pretty hot when they're worked hard or for a long tim...
Precharge resistor
Most controllers have banks of capacitors inside that help to smooth current flow. The capacitors gradually discharge w...
Curtis 1204-412: adjustable features
Note the adjustable current limiting (CL) and acceleration rate (ACC). Plug braking (PLUG) mode isn't used.

For maxi...
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