Boosting 208 1?

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chris kennedy

chris kennedy

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Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
Got a 1? 230V compressed air dryer that was relocated with no paper work. Air guy says 208 is no good. Consists of compressor, fan and electronic control panel.

Looking at a single tranny boost operation I see the equipment will see 120V on one ungrounded conductor and I'm guessing the other to be 80? out and around 150V.

Is this close to correct and will either motor or (my main concern) the control tranny be adversely affected by this?

Thanks
 
chris kennedy said:
Got a 1? 230V compressed air dryer that was relocated with no paper work. Air guy says 208 is no good. Consists of compressor, fan and electronic control panel.

Looking at a single tranny boost operation I see the equipment will see 120V on one ungrounded conductor and I'm guessing the other to be 80? out and around 150V.

Is this close to correct and will either motor or (my main concern) the control tranny be adversely affected by this?

Thanks
Click to expand...
As long as the 120V equipment is connected only to the not-boosted leg, all should be fine.

But I have to ask if the "air guy" is qualified enough to make the determination that "208 is no good". I'd be trying to locate some documentation, or contact the manufacturer, before going the boost xfmr route.
 
We run into a fair amount of equipment that does in fact want 230-240.

Refrigeration units on semi trailers. Run them at 208 and the motor overloads sometimes drop out.

Kitchen equipment with resistance heating elements.

7/11 slush drink machines.

But mostly we earn a living by installing what the customer requests. :)
 
iwire said:
We run into a fair amount of equipment that does in fact want 230-240.

Refrigeration units on semi trailers. Run them at 208 and the motor overloads sometimes drop out.

Kitchen equipment with resistance heating elements.

7/11 slush drink machines.

But mostly we earn a living by installing what the customer requests. :)
Click to expand...
I understand that, and agree some equipment will simply not perform as expected or desired on 208V.

Chris stated the equipment was relocated with no paperwork. I'm just saying I'd question the "air guy" making the call that 230-240V is required... without any documentation to back that claim up. On the other side of the coin, he may have first-hand experience with that make and model... but I simply cannot tell that from the OP. :happyno:
 
Smart $ said:
As long as the 120V equipment is connected only to the not-boosted leg, all should be fine.
Click to expand...
To my mind, there are two potential concerns which would have to be addressed by the manufacturer:

1. Does the machine use insulation at any point which is only good for 120V to ground and therefore might cause a problem with a voltage of 150 to ground?
2. Is there sensitive electronic circuitry in the machine which assumes that the two sides of the power circuit are balanced to ground, and there might be a problem with capacitively coupled net voltages to ground when the inputs are unbalanced.

I think that both of these are unlikely for both regulatory and design reasons, but they are conceivable.

Regarding item 2, there have been threads about excessive leakage current through the grounding conductor in heating appliances designed for 120/240 2-wire but driven from 240 delta instead. Still not a problem as long as the EGC is properly connected, but could lead to a voltage of up to 120V to ground on the metal parts if the EGC is compromised.
 
I tried the Ingersoll Rang web site yesterday but you have to open an account to get documents. I'm researching this because I'm not just going on someone's word.
 
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