Level 6 of 33 · Electrical lab
Direct-on-line motor starter
Level 6 of 33 in the Electrical lab: a free panel wiring exercise at Intermediate level. Wire the main circuit and the control circuit of a motor starter, and set the overload relay to the motor's full-load current. The overload is what saves the motor.
Goal
A direct-on-line (DOL) starter puts the full supply straight on the motor.
What you do
- Lock out the board at the isolator Q1: switch OFF, apply your lock and your tag.
- Prove it dead, live-dead-live: prove the meter on the proving unit, check the board reads 0 V, prove it again.
- Wire the 18 conductors of the schedule.
- Set the overload relay F3 to the motor's full-load current. Read it from the motor nameplate (M1). Set too high it will not protect the motor.
- Last. Restore power (tick the checklist, remove your tag and lock, switch Q1 ON), try every button, then run the FAT.
Done when
The factory acceptance test is marked against the panel you built.
- 18 conductors in the wiring schedule
- 4 dead checks before you touch the panel
Skills
Motor starters at Intermediate level.
Before you start
Level 5, Contactor with start and stop, comes first. Do it first if the ideas are new to you.
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