Brake and Motor Temperature
Motor electromagnetic / electromechanical brake
Electromechanical brakes are needed in critical applications where the disconnection of the motor or a lack of electric braking could be dangerous or harmful (i.e. falling suspended loads). Capitan XCR Servo Drive includes a brake output on the I/O connector J2. The brake output is an N-Channel MOSFET that can be PWM modulated to reduce effective brake voltage and thus power consumption when energized.
Its operation is usually configured for normally locked electromechanical brakes; that is, brakes that by default block the movement of the motor shaft when not powered. This kind of brakes increases the safety of the application because, in a drive power failure, the switch would be opened therefore the brake activated. Main ratings of the brake switch are detailed in the next table:
Specification | Value |
|---|---|
Type of output | N-Channel MOSFET, open-drain with a recirculation diode |
Maximum voltage | 50 V (connector limited) |
Maximum current | 1A (full temperature range) |
Delay after enabling the brake | 0 ~ 10000 ms (user configurable) |
Delay before release brake | 0 ~ 10000 ms (user configurable) |
Brake PWM frequency | 4 kHz ~ 40 kHz |
The next figure shows how the typical connection of the brake using a dedicated power supply.
The next figure shows the connection with a single power supply (< 50V systems). Note that it is possible to operate a 24 V brake with a 48 V power supply by configuring the maximum PWM duty cycle of the brake to 50%. In this case, configure it carefully before physically connecting the brake.
External temperature sensor
The Capitan XCR motor safety system connector allows the connection of an external temperature sensor based on changes of resistance (PTC thermistor, bimetal, NTC, PT100, silicon temperature sensors) to measure the motor temperature. The motion controller includes linearization for various sensors so the motor temperature can be read directly. Connection of the 2 wire sensors is shown next:
 | WARNING, the motor can be hot. The motor may become very hot > 70 ºC during operation. Do not touch it directly to prevent burns! The use of the temperature sensor is strongly recommended. |
 | CAUTION, motor overload. The Capitan XCR may allow currents that can damage or cause a fire to the motor. Always ensure that the continuous and peak current ratings of the motor are respected by adjusting during the drive configuration. |