# 208v to a 240v dryer



## retiredsparktech

Hotrod barn said:


> Came up today to a question,if a 240volt dryer can use 208volt to use.The spec. plate on dryer does not specifi 208 volts.It says 240volt.
> already had two different answers for this,what do you pros say ?


The dryer still uses 120 volts for the motor and the controls, by the the use of the neutral. 208 volts is derived from a three phase network. Probably in an apartment or a condo complex.
The drying time will be longer, as the element will be producing less heat, because of the lower voltage.


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## jmoon

We do this quite often since a lot of our panels are 120/208V. There shouldnt be any issues with doing this. More than likely the motor will operate at the same performance at either voltage, it will just draw more current at 208.

As sparktech said, the heating element will have less heat. Go for it.


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## wildleg

well, your options are:

1) use it, even though it won't work quite as well 

2) get the right dryer

3) buck/boost


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## Vintage Sounds

It works fine and people do it all the time. A little less heat but whatever. Except for commercial units I've never seen a true 120/208-only dryer anyway. Most I've seen just have two different current ratings like 120/240 23A and 120/208 21A.


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## RIVETER

Hotrod barn said:


> Came up today to a question,if a 240volt dryer can use 208volt to use.The spec. plate on dryer does not specifi 208 volts.It says 240volt.
> already had two different answers for this,what do you pros say ?


Clothes ...or hand dryer?


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## power

I have ran into the same issue with one of our welders. It can run on 208, you just need to turn the heat up a little to get the penetration.


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## RIVETER

power said:


> I have ran into the same issue with one of our welders. It can run on 208, you just need to turn the heat up a little to get the penetration.


I had that same issue with my first wife.:thumbsup:


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## Big John

Recently ran into a new dryer that had obviously just been replaced. I turned it on and was impressed that it was so quiet I could hardly hear it running. Then I noticed it was just _baaaarely _blowing out the tiniest bit of warm air. So there's proof that you can connect a 240V dryer to 208 and have it work, but it definitely doesn't work the same when you connect that 240V dryer to 120. :laughing:


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## hardworkingstiff

The power used by the heater will be 75% at 208 as it would be at 240. IMO, that's a lot.

Yes, it will work as others have said, but someone will most likely be disappointed.


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## retiredsparktech

Big John said:


> Recently ran into a new dryer that had obviously just been replaced. I turned it on and was impressed that it was so quiet I could hardly hear it running. Then I noticed it was just _baaaarely _blowing out the tiniest bit of warm air. So there's proof that you can connect a 240V dryer to 208 and have it work, but it definitely doesn't work the same when you connect that 240V dryer to 120. :laughing:


 Sorry buddy. The statement you made, does not hold true. 
AC motors are syncronous and will not run slower at lower voltages. The motor and controls, still receive the 120 volts, they were designed for.
I haven't seen an electric dryer lately, where you could connect it for straight 120 volts. I know years ago, that you could connect it for 120 volts, as it only used part of the element. It showed it on the connection diagram. It only took two hours to dry the load of clothes.


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## McClary’s Electrical

retiredsparktech said:


> Sorry buddy. The statement you made, does not hold true.
> AC motors are syncronous and will not run slower at lower voltages. The motor and controls, still receive the 120 volts, they were designed for.
> I haven't seen an electric dryer lately, where you could connect it for straight 120 volts. I know years ago, that you could connect it for 120 volts, as it only used part of the element. It showed it on the connection diagram. It only took two hours to dry the load of clothes.


I don't think John meant the blower was turning less rpms, I think he meant it was barely warm.


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## Big John

We're talking about different types of dryers. I was referring to a hand-dryer in a bathroom, not clothes dryer. My mistake.

That said, while I agree the speed of an induction motor in a dryer is related to frequency (though they aren't synchronous), a universal appliance motor definitely will spin more slowly if you reduce the voltage to it.


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## RIVETER

Big John said:


> We're talking about different types of dryers. I was referring to a hand-dryer in a bathroom, not clothes dryer. My mistake.
> 
> That said, while I agree the speed of an induction motor in a dryer is related to frequency (though they aren't synchronous), a universal appliance motor definitely will spin more slowly if you reduce the voltage to it.


Since you brought it up, let me ask...and I really don't know...in a public restroom are you required to GFCI protect a 208 volt hand dryer?


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## retiredsparktech

Big John said:


> We're talking about different types of dryers. I was referring to a hand-dryer in a bathroom, not clothes dryer. My mistake.
> 
> That said, while I agree the speed of an induction motor in a dryer is related to frequency (though they aren't synchronous), a universal appliance motor definitely will spin more slowly if you reduce the voltage to it.


Regarding an AC motor no-load speed, they will be running close to synchronous speed. When I was a motor tester, we always referred to the syncronous speed, relating to the number of poles @ 60hz.
We did build syncronous motors, for special purposes. They did have rotors, that were a unique design, where the company held the patents and the patent number was stated on the nameplate.


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## Meadow

retiredsparktech said:


> Sorry buddy. The statement you made, does not hold true.
> *AC motors are syncronous and will not run slower at lower voltages. *The motor and controls, still receive the 120 volts, they were designed for.
> I haven't seen an electric dryer lately, where you could connect it for straight 120 volts. I know years ago, that you could connect it for 120 volts, as it only used part of the element. It showed it on the connection diagram. It only took two hours to dry the load of clothes.


They will run slower as slip increases. Torque will go down, so speed will drop and slip goes up.


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## Hotrod barn

RIVETER said:


> Clothes ...or hand dryer?


It is a clothes dryer. 
Sorry for not saying so. 
Thanks


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## 99cents

Doesn't matter. With any hand dryer, you end up wiping your hands on your jeans anyway.


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## Hotrod barn

99cents said:


> Doesn't matter. With any hand dryer, you end up wiping your hands on your jeans anyway.


Plus the fact that they are NASTY inside.I have worked on a few.


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## Big John

Hotrod barn said:


> Plus the fact that they are NASTY inside.I have worked on a few.


 I've heard that. I've even heard the claim that they're supposed to be unsanitary because of bacteria.

It never made sense to me. It's just blowing really hot air, what could possibly be in there?


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## Hotrod barn

Big John said:


> I've heard that. I've even heard the claim that they're supposed to be unsanitary because of bacteria.
> 
> It never made sense to me. It's just blowing really hot air, what could possibly be in there?


 
The intake air sucks in dirt ,lint and everything else . makes the unit nasty inside.They never get cleaned out,just burnup and replaced.
I only use them when I have to.Rather use paper towels.
But I am going to run the dryer with 208.
thanks


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## micromind

My house is 120/208 3Ø, so the dryer is operated on 208. 

The only difference is that at 240, it took about 45 minutes to dry a load, at 208 it's about an hour. 

One advantage to 208 is lower current in the heater circuit; the element and its connections will last longer. Same with a water heater, plus if it's 4500 watts at 240, a 20 amp circuit and #12s is code compliant on 208.


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## retiredsparktech

The temperature regulating thermostats on the dryer are operating less often and should last longer. Also on the water heater. The recovery on an electric water seems eternal, so long luxurious showers are out.


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## Hotrod barn

retiredsparktech said:


> The temperature regulating thermostats on the dryer are operating less often and should last longer. Also on the water heater. The recovery on an electric water seems eternal, so long luxurious showers are out.


Thank you for this info.


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