Introduction In the world of industrial electric vehicle propulsion, few names carry as much weight as Curtis Instruments. The Curtis 1520 series controller is a powerhouse device designed for serious applicationsāthink Class 1 and 2 forklifts, stand-up counterbalance trucks, and large aerial work platforms. Unlike smaller PMAC or DC controllers found in golf carts, the 1520 is a complex, fully programmable AC induction motor controller.
| Blink Code | Fault Name | Likely Cause | |------------|---------------------------|-------------------------------------------| | 1-2 | Battery Under-voltage | Low pack voltage or bad connection | | 2-3 | Throttle Fault | Broken wire or out-of-range (0-5V) signal | | 3-4 | Main Contactor Welded | Contactor stuck closed | | 4-1 | Motor Temperature Sensor | Thermistor open or shorted | | 5-3 | Encoder Signal Loss | Broken encoder wiring or bad motor sensor | | 6-2 | Over-temperature (Controller)| Heat sink or fan failure |
| Pin | Signal | Description | |-----|----------------|----------------------------------------------------| | 1 | B+ (Logic Power)| +48V (switched via keyswitch) | | 2 | B- (Logic GND) | Ground for logic circuits | | 3 | Throttle Wiper | 0-5V analog input from accelerator pedal | | 5 | Interlock | Seat switch or operator presence (must be high) | | 8 | Encoder A | Motor speed feedback (differential) | | 9 | Encoder B | Motor speed feedback | | 14 | CAN-H | CANbus high (500kbps typical) | | 15 | CAN-L | CANbus low | | 21 | Main Contactor | Coil driver output (low side) | | 28 | Status LED | Blink code output for diagnostics |
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