EM-285 is a PWM-based speed controller for brushed DC motors. Motor voltage is regulated against variations in the supply voltage, helping the motor maintain the selected speed when the supply conditions change.
Adjustable RxI load compensation increases the motor voltage as the load rises, improving speed stability under changing mechanical loads. The current limit and potentiometer control range can be adjusted using onboard trimmer potentiometers.
The EM-285 controls motor speed using pulse-width modulation. The controller compensates for supply-voltage variations so that changes in the input voltage have less effect on the motor voltage and running speed.
Adjustable RxI load compensation helps maintain a steady speed when the mechanical load on the motor increases. The amount of compensation can be adapted to the motor and application.
When the speed potentiometer is turned to its zero position, the driver short-circuits the motor terminals for five seconds. This produces dynamic braking and allows the motor to be stopped or slowed more rapidly than by allowing it to coast.
The braking effectiveness depends on the motor, rotational speed, mechanical inertia and total circuit resistance.
The adjustable current limit restricts the motor current and can be used to protect the motor and mechanical system against excessive torque. The current limit can be adjusted between 1 A and 30 A using an onboard trimmer potentiometer.
The power stage includes an overvoltage shutdown function. This protects the driver if the supply voltage rises excessively, for example when energy generated during motor deceleration is returned to the supply line.
Undervoltage and overtemperature shutdown functions are also included. The power stage itself is not protected against a motor-output short circuit.
The driver supports selectable 2 kHz and 16 kHz PWM frequencies. The 16 kHz setting provides quieter motor operation, while the 2 kHz setting produces slightly lower power losses at the specified 20 A motor current.
The EM-285 is designed for straightforward panel installation through a 10 mm mounting hole. The unit has been EMC tested for typical industrial installations.
Because the power stage does not include short-circuit protection, a correctly rated external fuse must be installed in the application supply wiring.
| Supply voltage | 10–35 VDC |
| Overvoltage shutdown | 38 V |
| Undervoltage shutdown | 10 V |
| Start-up voltage | 11 V |
| Idle current | typ. 20 mA |
| Continuous motor current | max. 20 A (Ta < 50 °C) |
| Peak motor current | max. 30 A for 10 s |
| Power loss at 16 kHz | 5 W at 20 A |
| Power loss at 2 kHz | 4 W at 20 A |
| Adjustable current limit | 1–30 A |
| PWM frequency | 2 kHz or 16 kHz |
| Overtemperature limit | 90 °C |
| Motor and supply connectors | 2.5 mm² |
| EMC | EN 50081-2 and EN 50082-2 |
| Operating temperature (Ta) | −20…+60 °C |
| Weight | 85 g |
Ordering larger quantities +100pcs.
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