# Motor Starter Jumper L2 to T1???



## wirenut1110 (Feb 12, 2008)

It's done this way to utilize all the heaters on the starter.


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## InControl (Mar 20, 2007)

I havent seen contacts in series for a motor before, but I have seen a contactor with all three contacts in series for an electric brake. Kind of a safety measure, encase one set of contacts welds shut, there's two others to open to ensure the brake comes on when its supposed to.


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## MDShunk (Jan 7, 2007)

wirenut1110 said:


> It's done this way to utilize all the heaters on the starter.


Ditto. They probably had a 3-pole starter handy, and decided to utilize it that way for an extra measure of safety.


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## tburg jeff (Feb 21, 2009)

ya okay that makes sense to me.

thanks for your help

jeff


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## johnnebr (Jan 19, 2009)

If it is an iec starter it is wired that way so it does not see a single phase condition.


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## John Valdes (May 17, 2007)

johnnebr said:


> If it is an iec starter it is wired that way so it does not see a single phase condition.


Can you explain your comment? Are you talking "Smart" contactors or just the garden variety? Never had a contactor that could determine a single phase condition without some outside help.


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## jfwfmt (Jul 5, 2008)

Typical IEC starter has an electronic overload. It will have a current adjustment knob or screw rather than separate heater coils. It expects a balanced current on all three phases. It trips if it is unbalanced by some percentage or amount. This detects single phasing, but not phase reversal.

/s/ Jim WIlliams


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## wirenut1110 (Feb 12, 2008)

Yeah , It's not the contactor but the ol's. I think even NEMA starters with solid state OL's will trip if there's a phase imbalance. I think it's around 10%.


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## tburg jeff (Feb 21, 2009)

these are moeller starters, the electrician before me was old school and new what he was doing, I wire them the same way with Allen Bradley starters

jeff


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## johnnebr (Jan 19, 2009)

jfwfmt said:


> Typical IEC starter has an electronic overload. It will have a current adjustment knob or screw rather than separate heater coils. It expects a balanced current on all three phases. It trips if it is unbalanced by some percentage or amount. This detects single phasing, but not phase reversal.
> 
> /s/ Jim WIlliams


pretty well sums it up


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