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#43738 - 10/21/04 05:27 PM motor starter heater ratchet thingy  
maintenanceguy  Offline
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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#43739 - 10/21/04 06:25 PM Re: motor starter heater ratchet thingy  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,798
Brick, NJ USA
A mechanical function of the 'trip' mechanism that "opens" the contacts on overload seems to come to mind.

John


John

#43740 - 10/21/04 06:50 PM Re: motor starter heater ratchet thingy  
maintenanceguy  Offline
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?


#43741 - 10/21/04 06:56 PM Re: motor starter heater ratchet thingy  
resqcapt19  Offline
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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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