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motor starter heater ratchet thingy #43738
10/21/04 04:27 PM
10/21/04 04:27 PM
M
maintenanceguy  Offline OP
Member
Joined: Dec 2001
Posts: 300
Southern NJ, USA
On a square D motor starter. What's the function of those ratchet wheels on the side of the heaters?

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Re: motor starter heater ratchet thingy #43739
10/21/04 05:25 PM
10/21/04 05:25 PM
HotLine1  Offline

Member
Joined: Apr 2002
Posts: 6,919
Brick, NJ USA
A mechanical function of the 'trip' mechanism that "opens" the contacts on overload seems to come to mind.

John


John
Re: motor starter heater ratchet thingy #43740
10/21/04 05:50 PM
10/21/04 05:50 PM
M
maintenanceguy  Offline OP
Member
Joined: Dec 2001
Posts: 300
Southern NJ, USA
One heater melts and breaks and the "trip" pawl is released opening up the other two poles. I get that. But why a ratchet wheel? It doesnt seem to turn...or does it turn when it overheats?

Re: motor starter heater ratchet thingy #43741
10/21/04 05:56 PM
10/21/04 05:56 PM
R
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Quote
It doesnt seem to turn...or does it turn when it overheats?

Yes, it turns when it gets hot. There is a low melting point metal around the gear shaft and when it melts it lets the gear turn and that in turn opens the overload relay contact.
Don


Don(resqcapt19)

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