208 Dryer
- Thread starter domnic
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peter d
Senior Member
- Location
- New England
Nothing other than it will not get as hot and take longer to dry.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Will just take a little longer to dry {clothes ?}
I will nderpend upon what portion of the 208v depends upon 208v. Remember that both 208 and 240v are 120v to neutral. The motor most likely is 120v as well as the electronics and timer. Then it will depend upon if the heating element(s) are powered by a L-L voltage and/ or ,L-N voltages. Naturally a L-L voltage at 208v with is designed for 240v will generate less heat. But, should there be multiple elements rated at 120v each there will be no difference.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
It will take longer to get up to temperature initially, but once there it may simply have a higher thermostat on percentage during a given temperature and load cycle than if it were running on 240.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Since the dryer motor is usually 120V , I still am not sure why other than cost, the lower voltage will not affect the motor so other than what the other said and perhaps the listing of the unit it will work.
I hear this scenario all the time and IMO it is done because the dryers must be cheaper at 240V vs 208V
I hear this scenario all the time and IMO it is done because the dryers must be cheaper at 240V vs 208V
Carultch
Senior Member
- Location
- Massachusetts
Probably something to do with economy of scale. More production of dryers built for single/duplex family dwellings that have 120/240V services, than for dwelling units of large apartment complexes that have 120/208V phase-to-phase "sub-services".
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And because dryers built for 208 cannot be used on 240 while 240 can be used on 208 as long as motors are not involved.
JFletcher
Senior Member
- Location
- Williamsburg, VA
If the dryer motor is 120V, would it matter if it were 208 or 240V service? Either way it is 120V ungrounded and a grounded conductor. Are the motors typically L-L vs L-N?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
It would only be a potential problem if (as in an imported unit designed for the EU market) if the motor runs off the 240 rather than the 120. You are correct that the 120V motor would see 120V on either hookup.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I have seen straight 240V dryers but they are not common
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And who knows, they may have a motor which is rated for either 208 or 240....
junkhound
Senior Member
- Location
- Renton, WA
- Occupation
- EE, power electronics specialty
It will take a LOT longer...
The motor is at the same speed, there is 25% less heat applied.
If one looks at a psychometric chart, and does the calculations, and accounts for heat loss thru the dryer case, you get about 3X as long to dry.
Gets even worse for old dryers, where the NiCr wire has oxidized and gone up in resistance by 10-20%.
Had some 240 V appliances at the school once, needed to put auto transformers on the line or the workers complained about everything from clothes taking long to dry to water on the electric stove in big pots never even being able to come to a boil. (208/240)^2 = 75%
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I would think that the unit would say 240/208. To be honest I don't remember
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Maybe.
GD hit the nail on the head earlier, it will take longer to reach the "set point" temperature at the lower voltage, but exactly how long it takes to dry a specific load really depends on how much heat is needed to dry that load. Once the unit reaches set point it is just a matter of how much run time the element is needed to maintain temp, the drying time will still be the same if the set point is same either way. This comes down to design of the unit to some extent as well. If the designer made it based on heat needed at 208 volts, then running at 240 volts only gives you faster pre heat time, once up to temp the rest of the cycle is the same from the perspective of getting the clothes dry.
Most domestic units have a 120 volt motor and controls so that remains same either way. If the unit doesn't have a neutral, very possible it is designed for 208 or 240 operation if designed for North America anyway.
If designed for European countries, the motor will run at different speed if used on a 60 Hz system - if a typical induction motor. More modern equipment may not matter as they may have ECM motors. Probably more common with a washer then a dryer but I haven't got much experience with what is inside some of the newest dryers out there either.
- Location
- Massachusetts
Guys, have you looked at the tag on most residential dryers?
They are rated for both 208 and 240, they provide KW ratings for each.
They are rated for both 208 and 240, they provide KW ratings for each.
peter d
Senior Member
- Location
- New England
No kidding. :lol:
- Location
- Massachusetts
The motors are commonly 120.
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