Assuming a full size electric dryer, they're powered via two phase 120VAC. The heater only operates on 240VAC being connected between the 2 hot lines. The motor, timer and rest of it running on 120 volts hooked between one hot line of the supply and the neutral.

Dan O.
www.Appliance411.com
The Appliance Information Site

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I'm an American living in New Zealand. When I moved overseas 9 years ago, we bought all 220/240 appliances from a company specializing in appliances for overseas. Some of the appliances/electronics were truly 220/240v, some were dual voltage, and some we found (refrigerators) were actually 110v w/transformers installed in back (i.e. we paid too much!)
My dryer uses gas for heating but still requires electricity for the motor and timer and is wired for 220/240. Unfortunately, it is still in storage, so I can't examine it to find out if it's rewired, transformed, etc. IF your client had a gas dryer, then all they need is a stepdown transformer to supply the motor/timer? If it's all electric, I see the 2-voltage problem presented by the electrician's response.
You might contact one of the US suppliers of overseas appliances found by searching google.com "Overseas appliances"