Practical engineering guides for selecting, installing and configuring Electromen motor controllers. These application notes provide general guidance for common motor control applications and help explain the practical use of features found in Electromen products.
Note: Product features, electrical ratings and parameter settings vary between models. Always refer to the product-specific datasheet and user manual before installation or commissioning.
Selecting a motor controller requires more than matching only the supply voltage and motor current. The controller must also match the motor type, starting torque, peak current, braking requirements, feedback method, control signals and thermal conditions of the application.
First determine whether the motor is:
The motor type determines the required power stage and feedback method.
The controller supply voltage range must match the available DC supply. Always consider the maximum possible supply voltage, including ripple and voltage rise during regenerative braking.
The controller continuous current rating should be sufficient for the motor current during normal operation.
Continuous current capability depends on cooling, ambient temperature and installation conditions.
Motor current can be significantly higher during:
The controller should therefore be selected according to both continuous and short-term peak current requirements.
If the application requires rapid stopping or frequent direction changes, determine whether regenerative braking is required.
With a standard DC power supply, regenerative energy may require an external braking resistor. With a battery supply, the battery system may be able to absorb the returned energy.
Typical control methods include:
Open-loop speed control may be sufficient for simple applications. Closed-loop control should be considered when accurate speed or position control is required.
High-current applications may require:
| Requirement | Check |
|---|---|
| Motor type | DC / BLDC / Hall feedback / Positioning |
| Supply voltage | Nominal and maximum voltage |
| Continuous current | Normal operating current |
| Peak current | Starting and acceleration current |
| Braking | Freewheel / Dynamic / Regenerative |
| Control method | Analog / Digital / Modbus |
| Feedback | Open-loop / Hall / Position feedback |
| Cooling | Ambient temperature and mounting |
Important: Always verify the final controller selection from the product-specific datasheet and user manual.
A braking resistor is used when regenerative braking returns energy to the DC supply and the power source cannot absorb that energy. The resistor converts the returned electrical energy into heat.
A braking resistor may be required when:
The rotational energy stored in the load can be estimated by:
E = 1/2 × J × ω2
where:
Higher speed has a particularly strong effect because the stored energy increases with the square of speed.
Instantaneous resistor power can be estimated using:
P = V2 / R
where:
With a braking voltage of 30V and a 10Ω resistor:
P = 302 / 10 = 90W
This is the instantaneous power. The resistor does not necessarily need to be rated continuously for this power if braking occurs only for short periods. The resistor must, however, be capable of handling the required pulse energy.
The average braking power depends on how frequently braking occurs:
PAVG = EBRAKE × braking cycles per second
The resistor must tolerate:
Important: Always use the resistor range and braking threshold specified in the product-specific Electromen documentation.
Correct phase and Hall sensor wiring is essential for smooth and efficient operation of a sensored BLDC motor.
A typical BLDC motor has:
The controller switches the three motor phases according to the rotor position reported by the Hall sensors. The Hall sequence and motor phase sequence must therefore correspond correctly.
Incorrect phase or Hall wiring can cause:
Incorrect Hall phasing can cause very high motor current even at low mechanical load. Initial wiring tests should therefore always be performed with a reduced current limit.
Motor direction should normally be changed using the controller direction command after correct commutation phasing has been established.
Changing only two motor phase wires without making corresponding Hall changes may result in incorrect commutation.
Verify the Hall sensor voltage requirement before connection. Incorrect sensor supply voltage can damage the Hall sensors.
| Symptom | Possible Cause |
|---|---|
| Motor does not start | Incorrect Hall sequence, missing Hall signal or phase wiring error |
| Motor runs roughly | Hall and phase sequence mismatch |
| Very high current | Incorrect commutation phasing or mechanical blockage |
| Wrong direction | Direction command or phasing configuration |
| Runs only at some rotor positions | Missing or incorrect Hall sensor signal |
Important: Motor manufacturers do not always use identical wire colours or Hall sensor naming. Always verify the motor documentation when available.
Current Limit and I-Trip are related functions, but they serve different purposes. Understanding the difference is important when commissioning a motor controller.
Current Limit restricts the maximum motor current while allowing operation to continue.
Because motor torque is approximately proportional to current:
T ≈ kT × I
the current limit also acts as an approximate torque limit.
I-Trip is a protective shutdown function.
If the motor current remains at or above the current limit for longer than the configured trip delay, the controller stops the motor and generates a fault.
A simplified condition is:
I ≥ ILIMIT for t > tTRIP
| Function | Current Limit | I-Trip |
|---|---|---|
| Purpose | Control motor current | Protect against prolonged overload |
| Motor continues running | Normally yes | No, after trip |
| Affects torque | Yes | Indirectly |
| Uses delay | No | Typically yes |
| Requires reset after activation | No | Usually yes |
A motor may temporarily reach the current limit during acceleration. If the acceleration finishes before the I-Trip delay expires, the motor continues to operate normally.
If the motor is mechanically blocked, the controller may remain continuously at the current limit. I-Trip can then shut the system down after the configured delay.
The current limit should consider:
The delay should be long enough to allow normal starting and acceleration, but short enough to protect the motor and mechanics from prolonged overload.
| Problem | Possible Adjustment or Check |
|---|---|
| Trips immediately during normal start | Check load, current limit and I-Trip delay |
| Motor has insufficient torque | Check whether current limit is too low |
| Motor remains stalled without shutdown | Check whether I-Trip is disabled |
| Frequent I-Trip faults | Check mechanical load, acceleration ramp and motor sizing |
Important: The exact relationship between Current Limit and I-Trip varies between Electromen products. Refer to the product-specific parameter descriptions.
RS-485 is widely used for Modbus RTU communication because it provides reliable differential communication in industrial environments and allows multiple devices to share the same bus.
A typical connection includes:
Always follow the terminal naming used in the product documentation.
RS-485 should normally be wired as a linear bus:
Master — Device 1 — Device 2 — Device 3 — Last Device
Avoid long star branches because they can cause signal reflections and communication errors.
The physical ends of a long RS-485 bus should normally be terminated with the specified termination resistance.
A commonly used RS-485 termination value is approximately 120Ω, but the product-specific instructions should always be followed.
Each Modbus device on the same bus must have a unique address.
Two devices with the same address will cause communication conflicts.
All devices communicating on the same bus must use compatible settings:
Although RS-485 uses differential signalling, a common signal reference is recommended where required by the product documentation.
Large ground potential differences between devices should be avoided.
For reliable communication:
A Modbus RTU frame consists of:
Address | Function | Data | CRC
| Symptom | Possible Cause |
|---|---|
| No communication | A/B reversed, wrong address or incorrect communication settings |
| Communication works only occasionally | Termination, cable routing or grounding problem |
| One device works, several do not | Duplicate addresses or incorrect bus topology |
| Errors increase when motor runs | EMC interference or incorrect cable routing |
| Communication fails on long cable | Missing termination, wiring problem or excessive baud rate |
Important: Refer to the product-specific Modbus register definition document for available commands and register addresses.
Motor controllers use high-frequency switching and can generate electromagnetic interference if wiring and installation are not designed correctly. Good EMC performance depends on the complete system, not only on the motor controller.
Motor cables carry rapidly changing current and voltage. Keep them as short as practical.
Long motor cables can increase:
Keep motor and power cables physically separated from:
Avoid long parallel runs between power and signal wiring.
If signal and motor cables must cross, crossing at approximately 90 degrees can reduce electromagnetic coupling.
Twisted pairs reduce loop area and improve immunity to external interference. They are especially useful for:
Shielded cables may be required in electrically noisy environments. The shield should be connected according to the grounding concept of the complete machine or installation.
A shield is most effective when connected with a low-impedance connection rather than through a long thin wire.
Provide a low-impedance connection between conductive machine structures, enclosures and protective earth where required.
Poor grounding can contribute to:
Keep the DC supply wiring sufficiently short and use conductor sizes suitable for the motor current.
High resistance or inductance in the supply wiring can contribute to:
Install an external supply fuse according to the motor controller, wiring and application requirements.
The fuse primarily protects the supply wiring and system against excessive fault current.
Power integrity problems can occur if regenerative energy causes the DC supply voltage to rise significantly.
Use a braking resistor or another suitable energy absorption method when required by the application and supported by the controller.
Communication and low-level signal cables should be routed separately from motor and braking resistor wiring.
For RS-485, use a twisted pair and correct bus termination.
| Wiring Type | Recommendation |
|---|---|
| Motor cables | Short, separated from signal wiring |
| Supply cables | Short and correctly sized |
| Hall / Encoder | Separated from motor wiring, twisted or shielded if required |
| Analog signals | Keep away from switching power wiring |
| RS-485 | Twisted pair, linear bus topology |
| Shield connections | Low-impedance connection according to system grounding design |
Electromen motor controllers are components intended for integration into a complete machine or system.
The EMC performance of the final installation depends on the complete system, including:
The system designer or integrator is responsible for verifying that the complete installation complies with the applicable EMC requirements.
Important: Always follow the product-specific installation instructions in addition to these general recommendations.
These Application Notes provide general engineering guidance for Electromen motor controller applications. They do not replace the technical documentation of an individual product.
Electrical ratings, current limits, protection thresholds, I/O functions, parameter settings, braking resistor values and communication features vary between Electromen products.
Always refer to the product-specific datasheet, user manual and Modbus documentation before designing, installing or commissioning a system.
Electromen products are components intended for integration into a complete machine or system. The system designer or integrator is responsible for the correct application of the product and for compliance of the complete system with applicable electrical, EMC and safety requirements.
