# Inrush Current On Starter



## JRaef (Mar 23, 2009)

Usually on those big starters you use the line voltage for the coil, then use an interposing relay to switch that line voltage. If the _Sealed_ VA is 250, the inrush is likely in the 4-5kVA range (I looked up an A-B NEMA contactor with a 254VA sealed coil rating, the inrush is 4864VA). So if you try to do this with 120V, that's probably going to take a 25A T-D fuse or a 40A NON.


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## 460 Delta (May 9, 2018)

JRaef said:


> Usually on those big starters you use the line voltage for the coil, then use an interposing relay to switch that line voltage. If the _Sealed_ VA is 250, the inrush is likely in the 4-5kVA range (I looked up an A-B NEMA contactor with a 254VA sealed coil rating, the inrush is 4864VA). So if you try to do this with 120V, that's probably going to take a 25A T-D fuse or a 40A NON.


I understand using line voltage on these [240 here] but I have a 120 volt coil and felt lucky I found and saved this from the dumpster. I pretty much am in a take what you win and run what you brung situation here. The 10 amp TD fuse is holding, it just seemed a little large is all. The biggest starter I use is a 4 and that's kinda rare. The 5 is really big for the use, but it's what I have to work with.


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## gpop (May 14, 2018)

460 Delta said:


> I understand using line voltage on these [240 here] but I have a 120 volt coil and felt lucky I found and saved this from the dumpster. I pretty much am in a take what you win and run what you brung situation here. The 10 amp TD fuse is holding, it just seemed a little large is all. The biggest starter I use is a 4 and that's kinda rare. The 5 is really big for the use, but it's what I have to work with.



As long as the wire can handle 10 amps i do not see a problem. If the coil shorts it will clear a 10 amp fuse with out much of a problem. 

Now on a side note you have to make sure where ever you are pulling the 10 amps from can handle the additional load. Nothing like tripping a circuit and crashing a mcc.


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## 460 Delta (May 9, 2018)

gpop said:


> As long as the wire can handle 10 amps i do not see a problem. If the coil shorts it will clear a 10 amp fuse with out much of a problem.
> 
> Now on a side note you have to make sure where ever you are pulling the 10 amps from can handle the additional load. Nothing like tripping a circuit and crashing a mcc.


I used 16 gauge MTW wire so that will be fine, the power is pulled off one leg and the neutral. This is an old fashioned board and trough so no MCC to crash. here. Eventually the goal is to have this where the operator can select either A or B RPC from the batch room and then it'll be interlocked with the batch control so none of the functions will work until one of the RPC's are running.
There is plenty of spare wire in the trough to the control room, it's just going to be time consuming to identify them, that and move furniture to get to the JB with the wiring in it.
When I get all that accomplished, I'll spend a day moving caps around in the RPC's to balance the voltage and put some caps in the combo starters that will switch in and out with the motor so the voltage won't go from leading to lagging when all motors are on line and working.
RPC's are a hassle on r-mix plants, but are much better than using 10 and 15 HP single phase motors to run them.
I love my joblain:.


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## JRaef (Mar 23, 2009)

I just looked up a GE CR106 Size 5 starter coil data, 3360VA inrush, so 28A.


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## 460 Delta (May 9, 2018)

JRaef said:


> I just looked up a GE CR106 Size 5 starter coil data, 3360VA inrush, so 28A.


Wow, if it had a 600 volt coil it would still be at 5.6 amp inrush, that’s still a lot. If you don’t mind me asking, where did you get the specs on the current inrush for a GE, or is it still classified?!:surprise:


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## JRaef (Mar 23, 2009)

The GE "Buy Log" is still available on-line, even though this part of the old GE is now ABB.
Here's a link. :wink:


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## Rat_Face (Jun 21, 2019)

Also you mentioned they were old from storage? You took them apart and cleaned them, right? Pay attention to the drop out pads. I've had a number of issues with larger SquareD starters where prolonged inactivity or elevated ambient temps cause them to get sticky and actually restrict the armature movement blowing a fuse as you describe. Good luck!


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## 460 Delta (May 9, 2018)

Rat_Face said:


> Also you mentioned they were old from storage? You took them apart and cleaned them, right? Pay attention to the drop out pads. I've had a number of issues with larger SquareD starters where prolonged inactivity or elevated ambient temps cause them to get sticky and actually restrict the armature movement blowing a fuse as you describe. Good luck!


Yes, I completely stripped the unit, and inspected the contacts and the shade coils and brushed the mating surface of the laminations. 
This is a GE which is horizontal pull in and spring release so no drop pads.


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