Motortronics
Page 13
2.1.3
“Braking”
The ABC Series will enter the braking mode when the motor is given a stop command after being "Armed" (see
"JOG / ARMED" above). To prevent damaging current spikes, a factory programmed delay allows the existing
motor magnetic field to decay before DC is applied (see section 5.1). During the "BRAKING" mode, a set of N.C.
interlock contacts change state and disable the motor starter control circuit during the braking cycle (see section
4.2.2).
The ABC Series begins injecting a regulated DC braking current and simultaneously digitally times, controls the
Interlock Relay and monitors the Zero Speed Sense Circuit. Braking will continue until the first one of three
events occurs: 1) the Zero Speed Sense circuit determines the motor has stopped, 2) the "Brake Time" expires,
or 3) the unit receives a "Brake Disable" signal input. When braking is complete, the ABC Series releases the
Interlock Relay and is ready for another cycle.
2.1.4
Brake OFF
This LED illuminates whenever the ABC Series is not actively braking (either because the motor is on or the
previous braking cycle has been completed). The ABC Series provides a built-in, closed-loop sensing circuit that
accurately determines when the motor has stopped based on the subtle signals received from the unused motor
winding. If the Zero Speed Sensing circuit determines that the motor has come to a stop before the Brake Time
has expired, it will override the brake time setting and shut the ABC Series off. The "BRAKE OFF" LED will then
illuminate. NOTE: Since the Brake Time may expire prior to the Zero Speed override coming into play, this
circuit should not be used as a true Zero Speed indicator.
WARNING!
The ABC Series DC Injection Brake requires AC power for braking. Power loss before or during braking
will result in the loss of braking ability, which can be hazardous to personnel and/or equipment. If braking
to a stop is critical regardless of the availability of electrical power, mechanical braking should be
provided as a backup system. The ABC Series brake offers a Mechanical Brake Release Relay specifically
for this purpose.
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
