Tuesday, May 15, 2018

Don’t You Know the Stepper Motor Brake?

Applied Motion Products is pleased to announce the release of holding brakes for select step motors in the NEMA 23 frame size. These step motors provide additional functionality for applications which require holding torque to be maintained when power is removed from the motor. Holding brakes offered by Applied Motion are spring-set type brakes that must be powered by 24 volts DC to release the brake mechanism. This is commonly referred to as “power off” and is the preferred style for motion control applications. Controlling the brake is handled by a discrete output on the stepper drive or another controller like a PLC or motion controller. 
Many stepper motor online drives offer outputs specifically designed to control the holding brake, such that the brake will be automatically engaged whenever the motor is unpowered (and automatically disengaged when the motor is powered or moving) A common application for holding brakes is one in which a belt drive linear actuator is mounted vertically. When power is removed from the motor the belt and load can drop, potentially causing harm to the machine and/or human operators. Holding brakes can help to alleviate this unsafe condition by automatically holding the motor and load in position even when all power has been removed from the motor.
Nema 11 Stepper Motor Bipolar L=51mm w/ Gear Ratio 14:1 Planetary Gearbox
Additionally, a large majority of our drives have dedicated brake outputs that can be wired to a relay to control operation of the brake. We even offer a delay time to either engage or disengage the brake. This is an important feature so that the motor does not interfere with the proper operation of the spring applied brake causing premature brake failure or damage to the motor. The brake output control function is simply found in the ST Configurator™ software in the I/O Configuration window. This stepping motor brake new 1.8° and 0.9° PKP Series 2-phase stepper motors are available with built-in power-off activated preassembled electromagnetic brakes. 
Nema 24 Stepper Motor 4.0Nm(566 oz.in) w/ Brake Friction Torque 2.0Nm(283oz.in)
When power is accidentally cut off due to unexpected events, such as a blackout, the electromagnetic brake holds the load in position to prevent it from moving. When the motor is at standstill, it can be held by the electromagnetic brake. The brake can also be used to suppress the heat generated from the motor by switching off the motor current and using the brake as the holding function. The new PKP Series stepper motors are available in both bipolar and unipolar configurations and in the following frame sizes: 35 mm (1.38 in.), 42 mm (1.65 in.) and 56.4 mm (2.22 in.). PKP26 models (56.5 mm/2.22 in. frame size) come with an 8 mm shaft.

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