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Old 04-07-2009, 12:04 AM   #16
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Split 3-phase


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Originally Posted by InPhase277 View Post
?? That's what the OP is talking about. He has a 208/120 V service. He has used two legs to send single phase 208 to his saw and thinks the lower voltage is causing his problem.
What makes you say that? In my area there are alot of 240/120 center-tapped Delta systems in the older shops.

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Old 04-07-2009, 12:11 AM   #17
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Split 3-phase


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Originally Posted by Silk View Post
What makes you say that? In my area there are alot of 240/120 center-tapped Delta systems in the older shops.
Because he said so right in his post. He said he has a 230 V single phase motor connected to two legs of a 208 V three phase system.

I don't think his problem is voltage. I think he has a bad start capacitor.
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Old 04-07-2009, 12:15 AM   #18
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Split 3-phase


No he didn't, read it again, he said the electrician "split the 3 phase" which doesn't make any sense. Most of the shops in my area have a high leg delta setup so 120 lighting is available and also 240 3 phase for the motors, and also 208. I would not be so sure that the OP's shop isn't wired the same. By the way, I don't think the voltage is the problem either, but I'm also not so sure either him or his electrician know what they are talking about.

Last edited by Silk; 04-07-2009 at 12:20 AM.
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Old 04-07-2009, 12:26 AM   #19
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Split 3-phase


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Originally Posted by Silk View Post
No he didn't, read it again, he said the electrician "split the 3 phase" which doesn't make any sense. Most of the shops in my area have a high leg delta setup so 120 lighting is available and also 240 3 phase for the motors, and also 208. I would not be so sure that the OP's shop isn't wired the same. By the way, I don't think the voltage is the problem either, but I'm also not so sure either him or his electrician know what they are talking about.
The 208 of a delta high leg generally is a by-product and isn't meant to power any loads. But the OP's description of "split 3-phase" I took to mean "two wires of the 3-phase", not "240/120 V delta with a center tapped transformer".

He is a lay person and thus described it as "split". Usually, lay persons are unaware of the 208 V available from a delta system, and so when I hear them mention 208, it is usually in connection with a wye system. At any rate, I'm not saying you are wrong. He could have a 240 V system, but I didn't read that from his post. It reads to me like he has a 208/120 V wye, and his electrician wired his saw as single phase 208 V.
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Old 04-07-2009, 12:38 AM   #20
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Split 3-phase


Take it easy,now. You'll have to excuse me if I have caused confusion by the wording of my post. I know very little about 3-phase. All I know is what the electrician has told me. He said that the the type of 3-phase I have does not allow for the 240, only 208 and the 120 to power the lights and regular outlets.

Just to add a whole other element here, can the power to my meter be changed to single phase, or is that a big deal?

Mark
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Old 04-07-2009, 08:45 AM   #21
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Split 3-phase


Yes your power at the meter can be converted to single phase

if

1. YOu are willing to pay the cost to change it over including installing a new meter and running lines to a different pole transformer,
2. 120/240 volt single phase is available on your section of the street, namely a pole transformer delivering that is within a few buildings of yours.

(The lines from the meter to your panel could stay the same)
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Last edited by AllanJ; 04-07-2009 at 08:48 AM.
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Old 04-07-2009, 02:55 PM   #22
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Split 3-phase


The meter base will need to be changed as well. A 120/208 wye meter base is 7 jaw, a single phase is 4 jaw.

If you really need the full 240, a buck-boost transformer would likely be the best option. It will need to be 0.5 KVA, with this size you can boost either 24 or 32 volts for a 13 amp load. It'll cost about $150-200. Not a huge number of electricians know how to connect it, but it can be adequetly described right here, if needed.

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