Starter Size

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mull982

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I have a 40hp motor and the only starter I had avaliable was a size 4 starter. I know typically you would use a size 3 starter for this application, but as long as my overloads are sized correctly is there a problem with using a larger size starter on a motor, in this case a size 4 starter?
 
No problem, just as long as the overloads are sized correct. Not sure off hand what size starter, but the actual size will change, and the physical size of the overload will change.
 
mull982 said:
I have a 40hp motor and the only starter I had avaliable was a size 4 starter. I know typically you would use a size 3 starter for this application, but as long as my overloads are sized correctly is there a problem with using a larger size starter on a motor, in this case a size 4 starter?
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One thing you need to keep watch out for. If you are replacing an existing starter with a bigger one, the transformer (if it has one) may be too small for the bigger starter. I have ran in to this several times.
 
(assuming a combination type starter) There may be an issue with the overload relay heater element and the sizing of the branch circuit short circuit and ground fault protective device. A maximum sized for the line side OCPD is specified for some overload relay elements. Also this OCPD may be too large for the circuit based on Table 430.52.
 
don_resqcapt19 said:
(assuming a combination type starter) There may be an issue with the overload relay heater element and the sizing of the branch circuit short circuit and ground fault protective device. A maximum sized for the line side OCPD is specified for some overload relay elements. Also this OCPD may be too large for the circuit based on Table 430.52.
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can i ask a good question here, while we are on the topic?

i have some ge size 3 starters some are 30yrs in service
i can buy square d for 300 less than ge, are there any problems
mounting them in this ge combination switch/starter enclosure?

these are ahu starters, 40 hp motors
 
steveng said:
... i can buy square d for 300 less than ge, are there any problems
mounting them in this ge combination switch/starter enclosure? ...
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Could be a code issue. All the combination starters I deal with are mag only CBs. NEC requires the combination to be part of a listed assembly. I would think that installing a SQD starter in a GE combo starter with a mag only CB voids the listing.

carl
 
coulter said:
Could be a code issue. All the combination starters I deal with are mag only CBs. NEC requires the combination to be part of a listed assembly. I would think that installing a SQD starter in a GE combo starter with a mag only CB voids the listing.

carl
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That would be correct.

But I would also question that vast disparity in price, manufacturers are not that far off from each other. Either you are not looking at truly equivalent components, or you are not buying them right. For instance, if the GE combo starter was using a NEMA rated starter and the Sq. D you are looking at is a Definite Purpose starter, it is not only illegal for you to use the DP as a replacement, but it is in no way "apples to apples" for comparison. Or if you are getting a price on the GE starter from someone who is not an authorized GE distributor, that may be the problem too.
 
coulter said:
Could be a code issue. All the combination starters I deal with are mag only CBs. NEC requires the combination to be part of a listed assembly. I would think that installing a SQD starter in a GE combo starter with a mag only CB voids the listing.

carl
Click to expand...

thanks carl

thanks jaref
 
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