EMR-5000
IM02602012E
Motor Starting and Control Module
Available elements:
MStart
General – Principle Use
The motor start control logic is the core control and protective function for a protective device. The logic includes the
motor operation state monitoring, motor state transition control, starts limit monitoring, state transition trip, and
emergency override.
Motor Cycle Monitoring
The basic motor operation states can be classified as four states that include:
1.
Start cycle;
2.
Run cycle;
3.
Stop cycle; and
4.
Trip state.
Under normal conditions, the motor operations should go through stop, start, run, and stop cycles that are referred to as
a complete operation sequence; while under certain abnormal conditions, the motor could go from start to stop, or start
to trip, or run to trip. If other protection trips occur at either the start or run cycle, the motor will be forced to go to trip
mode. After motor currents are terminated, the motor will go into the stop cycle. A motor start is blocked by the hidden
state “Block” as shown in the motor start diagram, if any of the following conditions are noted - motor starts limit, starting
frequency, thermal and mechanical constraints. The User may choose to use the blocked state to block the motor from
starting or use it as an alarm or indication.
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