Does anyone know how to split the 240 V wire components of a dryer from the 120 V?

Question

We are living on an island where the electrical grid is already 240V. We shipped a US dryer here and are trying to figure out how to wire it properly (me and local electricians). From my research dryers use 240 V only for the heater and motor. The panel components just use 120 V. They need two live wires to combine and make 240V for the heater and motor. Dryers here are EXTREMELY expensive, and hard to come by so we are trying to make this work to make the wife happy.

The house we are in is wired so that it has the US 120 V. and the 240 V outlets. They have a big transformer by the breaker box doing the step down from 240 to 120 for all the 120 V outlets in the house.

The current idea is to separate the 240 V. components from the 120 V. components. So have two plugs coming from it. One that connects to the 240 V plug to power the heater and motor. The other plug to come and plug into the 120 V. outlet.

After looking at the wiring inside it looks like one live wire stays up top to power the control panel. While the other life wire along with the ground goes below to connect at a junction on the motor to power that and the heater. I also notice a neutral white wire going from the electrical control panel up top, goes down to the bottom and meets at that same junction. I imagine to give down below the extra 120 V. to become 240V?

So finally the question. Can I just get rid of that neutral wire to separate the two systems and wire them to two separate plugs???

Here is the electrical schematic that was inside the dryer. Not sure how to read it but hopefully it helps.

Answer 1

Oh no! You can't do that hack-a-dack.

That transformer probably has what you need, but you need to draw the 120/240 power in a very particular way. You cannot just slapdash a 120V plug and call it good. If you do, there's a 50/50 chance that you'll plug it in and BANG!

The professional installer who installed that transformer, or an electrician of equal skill, will know the correct way to extract 120/240V from that transformer. Call him and have him install a NEMA 14-30 receptacle with appropriate circuit protection.

Hacking the dryer to have totally separate power systems for heater and motor isn't outside the realm, but it's going to require a fair quantity of additional parts, because the parts you need are not in the dryer and won't be available on a 240V island. Notably, 2-pole relays where the dryer now uses 1-pole. The cost and time delay to source those parts, iteratively, is probably going to be prohibitive.

Answer 2

Just about every motor out there is labeled for 50/60 HZ so that should not be the main problem.

The problem is the heater coils take 240 volts to heat properly.

Just real quick scanning the schematic and it looks like you could connect the black and white to 120 volts and see if everything will work except the heat.

I might try that if I was desperate but if dryers are real expensive there then smoking one because you wired it wrong will be even more expensive.

I believe best answer is to get a 5KVA transformer that goes from 240 volt single phase to 240/120 single phase. (We call this a derived system and we do it all the time with larger transformers going from 480 volt delta without a neutral to 480/277 with a neutral or to 208/120 with a neutral.) The key is that you have to establish a ground at the transformer and bond the neutral to it.

This is not a DIY project unless you do this for a living. You should find an experienced electrician to help you.

Good luck!