EM-A43 is a regenerative braking load designed for DC motor systems. When a motor decelerates, it can operate as a generator and return energy to the DC supply, causing the supply voltage to increase.
The EM-A43 monitors the DC-bus voltage with an adjustable comparator. When the selected voltage threshold is exceeded, the power resistors are connected across the supply and convert the regenerated energy into heat. This helps limit the voltage rise and protect other equipment connected to the DC bus.
Regenerated energy is produced during rapid motor deceleration, lowering of a mechanical load or other operating conditions in which the motor is driven by the connected machinery.
If the DC power source cannot absorb this returned energy, the supply voltage rises. The EM-A43 provides an additional energy-dissipation path by switching its braking resistors across the DC supply.
The switch-on threshold is adjustable from 20 to 60 V. The recommended setting is approximately 10–15% above the highest normal idle voltage of the power supply.
For example, with a power-supply idle voltage of 26 VDC, a suitable initial switch-on setting is approximately 30 V:
26 V × 1.15 ≈ 29.9 V
The selected threshold must also remain safely below the overvoltage limit of the motor controller and all other devices connected to the DC bus.
The braking resistors can be connected in two configurations, providing a nominal braking-load resistance of either 1.4 Ω or 5.6 Ω. The appropriate connection depends on the system voltage, required braking current, regenerated energy and permitted thermal load.
At a 30 V DC-bus voltage, the theoretical currents are approximately:
A red onboard LED indicates when the power resistors are active. During intermittent regenerative braking, the LED may switch on and off as the DC-bus voltage moves across the switching threshold and hysteresis range.
The EM-A43 includes overtemperature protection with a specified limit of 160 °C. The braking resistors can become extremely hot during operation, and the device must be installed with sufficient clearance from wiring, heat-sensitive components and combustible materials.
| Function | Regenerative braking load |
|---|---|
| Operating voltage | 12–60 VDC |
| Idle current | 5 mA |
| Adjustable switch-on threshold | 20–60 V |
| Recommended threshold setting | Approximately 10–15% above the highest normal idle supply voltage |
| Typical braking current | 10–20 A |
| Selectable braking-load resistance | 1.4 Ω or 5.6 Ω |
| Switching hysteresis | Typically 10% |
| Active indication | Red onboard LED |
| Overtemperature limit | 160 °C |
| Weight | 135 g |
Ordering larger quantities +100pcs.
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