EM-174A is a bidirectional speed controller for brushed DC motors. The controller regulates the motor voltage, making it suitable for use with both regulated and unregulated DC power supplies.
Motor speed can be commanded using an external potentiometer or a direct analog voltage signal. Adjustable RxI load compensation helps reduce motor-speed variation caused by changes in mechanical load.
The controller can be configured for 12 V or 24 V applications. Its 25 kHz PWM power stage provides efficient and quiet motor operation.
The motor-speed command can be provided using an external potentiometer or a direct analog voltage signal. The input supports bipolar ±5 V and ±10 V signals as well as unipolar 0–5 V and 0–10 V signals.
The control range can be scaled using the range-adjustment trimmer. This allows the available analog command range to be matched to the required motor-voltage range.
The controller provides regulated −5 V and +5 V auxiliary voltages for an external control potentiometer. This allows a single centre-position potentiometer to control both motor direction and speed.
The motor stops when the potentiometer is in its centre position. Turning the potentiometer to either side commands the corresponding direction, with motor output increasing as the control is moved farther from the centre.
Motor direction can be selected either by the polarity of a bipolar analog command or by the separate direction-control input when a unipolar control signal is used.
The forward state is selected when the direction input is at 0–1 V or left open. The reverse state is selected by applying a 4–30 V signal to the input.
When the requested direction changes, the EM-174A first waits for the motor to stop before applying power in the opposite direction.
This prevents an immediate reversal while the motor is still rotating and helps reduce current peaks and mechanical stress during direction changes.
Motor-voltage regulation compensates for variations in the supply voltage, helping to maintain a stable commanded motor-voltage level.
Adjustable RxI compensation increases the motor voltage as motor current rises. This helps compensate for the voltage drop caused by motor winding resistance and reduces speed loss when mechanical load increases.
The adjustable current limit protects the motor, power stage and mechanical system if the motor stalls or the mechanism becomes jammed.
The current limit can be adjusted internally from 0 A to 12 A or controlled externally using a 0–5 V signal, where the full input range corresponds to a current-limit range of 0–12 A.
The acceleration ramp gradually increases the motor voltage during start-up. This provides a smoother start and reduces sudden mechanical and electrical loading.
The ramp time can be adjusted from immediate response up to three seconds.
The controller can be optimized for either 12 V or 24 V motor applications. In the 12 V setting, the motor-voltage range is 0–15 V. In the 24 V setting, the range is 0–29 V.
The EM-174A is suitable for conveyors, feeders, pumps, fans, valve actuators, positioning mechanisms and other brushed DC motor applications requiring bidirectional speed control, adjustable torque limitation and controlled acceleration.
| Supply voltage | 12–32 VDC |
| Overvoltage protection level | 40 V |
| Idle current | approx. 30 mA |
| Continuous motor current | 8 A |
| Peak motor current | 12 A at 50% duty cycle |
| Motor-voltage range, 12 V setting | 0–15 V |
| Motor-voltage range, 24 V setting | 0–29 V |
| Adjustable current limit | 0–12 A |
| External current-limit control | 0–5 V corresponds to 0–12 A |
| Adjustable acceleration ramp | 0–3 s |
| Voltage loss | 1 V at Im = 8 A |
| PWM frequency | 25 kHz |
| Auxiliary voltages | −5 V and +5 V, max. 10 mA |
| Control potentiometer | 1–50 kΩ |
| Bipolar control-voltage ranges | ±5 V or ±10 V |
| Unipolar control-voltage ranges | 0–5 V or 0–10 V |
| Direction-input impedance | 10 kΩ |
| Reverse direction input | 4–30 V |
| Forward direction input | 0–1 V or open circuit |
| Operating temperature (Ta) | −20…+70 °C |
| Dimensions | 65 × 73 × 30 mm |
| Weight | approx. 80 g |
Ordering larger quantities +100pcs.
For volume discounts pls. see the Contact Info for Electromen distributors. If you didn´t find your country distributor then ask direct offer from office@electromen.com
