120/208v Service-230v Commercial Dryer

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Talmadge

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Many years ago as an apprentice I saw this scenario on a job and it had a disastrous outcome. Now I'm face with nearly the same thing and don;t want the same results.

When I was an apprentice we were wiring a job at a commercial laundry. The main service was 277/480volt, the designer had designed the low voltage to be 120/208volt, which is the standard here. The dryers arrived and they were 230v (all three phase). The Journeyman I was working with connected the 230v dryers to the 208v circuit, telling me that 208 and 230 function the same phase to phase and it didn't matter. However, evidently that wasn't the case with this dryer that required a high leg. Two days later it caught fire and my boss had to buy the dryer. The problem was solved by installing a different transformer that supplied the correct voltage to the dryers.

Now, years later I'm faced with the same problem, except now, I'm the boss and I really don't want to buy a burned commercial dryer. My situation is different because I don't have 277/480v coming into the building, the service is 120/208v from the power company. I called the supply house and asked if they had a transformer with a 120/208 volt primary and a 230 volt secondary, they did, but is a special animal, a 230 volt Open-Delta that only outputs 230 volts.

I'm at a loss here and don't have the time or money for trial and error or experimentation, I have to get this right the first time or I'm sunk. Any advice would be appreciated.
 
I'm surprised that a 3Ø, 230 volt dryer wouldn't run fine on 3Ø, 208 volts with just a lower output. Why did the original dryer require a high leg?
 
1) Get the spec sheet for the dryer. Find out exactly what the manufacturer requires, and then supply that.

2) You almost certainly do not need a high leg delta for this dryer, but it is possible.

3) if you just need 230V then standard buck/boost transformers will work

Jon
 
winnie said:
1) Get the spec sheet for the dryer. Find out exactly what the manufacturer requires, and then supply that.

2) You almost certainly do not need a high leg delta for this dryer, but it is possible.

3) if you just need 230V then standard buck/boost transformers will work

Jon
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This is all I was given.
 

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Looked it up, Ouch! Someone should have ordered the right dryer! About $3k in transformers for wye conn connection, you could save a little using an open delta.
 
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Talmadge said:
I called the supply house and asked if they had a transformer with a 120/208 volt primary and a 230 volt secondary, they did, but is a special animal, a 230 volt Open-Delta that only outputs 230 volts.
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What you should ask for is a 208v delta primary and a 240/136v wye secondary for easiest bonding.
 
infinity said:
I'm surprised that a 3Ø, 230 volt dryer wouldn't run fine on 3Ø, 208 volts with just a lower output. Why did the original dryer require a high leg?
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I'll second that and also can't believe it would require a high leg to function correctly. I wonder if that story in OP didn't actually somehow end up with the 480/277 either directly or some sort of interconnection involved? Or maybe a high limit thermostat is what actually failed? 240 element operating at 208 can still overheat if controls are not functioning correctly. Though the fact the unit caught fire could also suggest foreign material somehow got someplace it shouldn't be and that is what caught fire?
 
I’m betting there is a multi volt control transformer, and the op’s previous experience with a fire, was probably due to undervoltage to the contactor(s), which probably caused the fire. Like others have said, I believe the motors would probably tolerate the lower voltage, at least longer than a couple of days.
 
electrofelon said:
Can you confirm or clarify whether the different voltages are different model dryers or each one can be connected internally for different voltages? Looking at the amp draw strongly implies that the same dryer is used with the same connections whether it be 208 or 240 volts service.
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So the spec sheet is not very clear on which lines are different models, but I did a little digging and it appears there is a 208 model and a 220-240 model. The resolution was poor on the spec sheet and I thought the 208 amp draw was 68, but I pulled up a better one ad it is 88. The 220, 230, and 240 amp draws all imply the same heating element. Also online I saw a vendor selling this unit and you had to select 208 or 240.

So if all that is true, maybe talk to the manufacturer about options for using the 240 version on 208. You would have lower wattage from the heating elements and the motor will run hotter. Someone ordered the wrong dryer it appears.
 
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