Bowling Alley Motors

[harborrick]

I am installing 2 new 120/208 3ph 3 wire subpanels
I have 32 bowling lanes that are being rebuilt with motors etc.
Total load per lane is 18 amps per plug at single phase 208v
However these are split second on and off loads.

Since I have 32 new circuits I have split into 2 panel boards.

Trying to see if I need to design at 288 amps? Or do I get demands for these motors.
Any help would be appreciated.
Thank You in advance

 

[mgookin]

Are they all going to do the same thing at the same time such as from a master control or timer that says the facility is now open or closing? Or is there a master test that activates them all at the same time?

These motors clear & reset pins? Put the balls on the return?

 

[kwired]

I am installing 2 new 120/208 3ph 3 wire subpanels
I have 32 bowling lanes that are being rebuilt with motors etc.
Total load per lane is 18 amps per plug at single phase 208v
However these are split second on and off loads.

Since I have 32 new circuits I have split into 2 panel boards.

Trying to see if I need to design at 288 amps? Or do I get demands for these motors.
Any help would be appreciated.
Thank You in advance

I'm not seeing how you are getting 288 amps.

If we would assume 33 units just to get even balance - I am seeing 18 x 1.732 amps for three units balanced across the lines x 11 more sets of three = about 343 amps.

I don't see the NEC having any specific demand factor you can apply, but I can almost guarantee you will never see all 18 amps from all 32 units at the same time as well. Maybe manufacturer of such equipment can be of help in determining typical load patterns? I would bet if you supplied all of them from a 100 amp feeder it would seldom if ever trip the main overcurrent device, if that isn't quite big enough I bet 150 amps is.

 

[harborrick]

I'm not seeing how you are getting 288 amps.

If we would assume 33 units just to get even balance - I am seeing 18 x 1.732 amps for three units balanced across the lines x 11 more sets of three = about 343 amps.

I don't see the NEC having any specific demand factor you can apply, but I can almost guarantee you will never see all 18 amps from all 32 units at the same time as well. Maybe manufacturer of such equipment can be of help in determining typical load patterns? I would bet if you supplied all of them from a 100 amp feeder it would seldom if ever trip the main overcurrent device, if that isn't quite big enough I bet 150 amps is.

Correct all will not be going on at same time.
There are 32 units total. However these are single phase 208volts each not 3 phase.

It mostly depends how many people bowling etc.
I will try and call factory for some more help.
I have never seen so many small motors with any special demands.

Thanks Again

 

[harborrick]

I'm not seeing how you are getting 288 amps.

If we would assume 33 units just to get even balance - I am seeing 18 x 1.732 amps for three units balanced across the lines x 11 more sets of three = about 343 amps.

I don't see the NEC having any specific demand factor you can apply, but I can almost guarantee you will never see all 18 amps from all 32 units at the same time as well. Maybe manufacturer of such equipment can be of help in determining typical load patterns? I would bet if you supplied all of them from a 100 amp feeder it would seldom if ever trip the main overcurrent device, if that isn't quite big enough I bet 150 amps is.

Correct all will not be going on at same time.
There are 32 units total. However these are single phase 208volts each not 3 phase.

It mostly depends how many people bowling etc.
I will try and call factory for some more help.
I have never seen so many small motors with any special demands.

Thanks Again

 

[kwired]

Correct all will not be going on at same time.
There are 32 units total. However these are single phase 208volts each not 3 phase.

It mostly depends how many people bowling etc.
I will try and call factory for some more help.
I have never seen so many small motors with any special demands.

Thanks Again

I understood there were 32 units and that they were single phase, but you do intend to balance them across all three lines of a three phase system don't you? I simply assumed 33 for simplicity because that would be an even balance, ever set of three units balanced across the phases would draw 18 times 1.732 amps =31.176 times 11 sets of three =342.936. Take away one single phase unit and you only have around 312 on two of the phases the remaining phase should still see about 343. I am not seeing how you came up with 288 is all I was trying to point out.

I would also guess the load varies and that quite a bit of the time may not even be close to 18, but don't know much about these machines. Would guess they do run at an idle so to speak quite often, and load increases for a short period each time a user bowls a frame.