Automatic Voltage regulator rating

[Alvs]

Hello Everyone,
I'm here in a country which has a 220v single phase.
My wife's $700 Microwave/Convection oven just arrived from the US. The rating of this appliance is: 110v, 1750 watts, 15 amperes.
I've talked to suppliers here and was told to buy an AVR with a rating(wattage) 5 times more of the rated 1750 watts. The vague reason behind is... "there a heating element in the appliance." It makes no sense. Another one says, 3 times more than the 1750 watts. This means the price tag would also be 3-5 times more now.
I need sound advice from electric appliance experts, maybe with an electrical engineering background or similar. What is the ideal stepdown AVR rating for my oven at 220 volts should I be using?
Your help is highly appreciated. I don't want to burn the oven and die... hahaha.
As the saying goes; "Happy wife, Happy life" ;-)
Cheers!

 

[phyzguy]

Have you considered a transformer instead of an AVR? They might be cheaper. This is how I ran US appliances when I lived in Europe.

 

[pedro the swift]

An AVR??just what is that in this application? Use a 220V to 110V transformer rating 2 to 2.5 KVA. Probably won't be cheap or light. Can't understand why you would import a 110v Appliance anyway. Are they not available in your location at the correct voltage? And $700? is it gold plated?. We can buy here much more cheaply.

 

[Alvs]

Have you considered a transformer instead of an AVR? They might be cheaper. This is how I ran US appliances when I lived in Europe.

Thank you for your reply phyzgys. I'm considering a stepdown transformer with AVR because of the spikes here. I don't want to damage the oven. I'm considering the the Imarflex or Meiji brands but I don't know how many watts would I be buying. Thanks again for your reply.

 

[Alvs]

An AVR??just what is that in this application? Use a 220V to 110V transformer rating 2 to 2.5 KVA. Probably won't be cheap or light. Can't understand why you would import a 110v Appliance anyway. Are they not available in your location at the correct voltage? And $700? is it gold plated?. We can buy here much more cheaply.

"An AVR??just what is that in this application?"
- Because of the spikes here, it is recommended to have an AVR.
"Use a 220V to 110V transformer rating 2 to 2.5 KVA. Probably won't be cheap or light."
- This is not recommended here because of the same reason above.
"Can't understand why you would import a 110v Appliance anyway. Are they not available in your location at the correct voltage? And $700? is it gold plated?"
- You're correct, the model is not available here. The 220v version from Australia or Europe has a pricetag of $300 more + shipping. Haha... Goldplated? ..Haha, Nuh. This an average price of over-the-range microwave/convection oven.
"We can buy here much more cheaply."
- Where is "here"?
Thanks anyway for the reply.

 

[Guineafowl]

Although the UK is 240V, we often use 110V tools on building sites, powered by step-down tranformers. The neutral/earth comes from the centre tap so there is maximum 55V between either line conductor and earth, for safety in wet environments.


This one costs under £50 and is rated 3.3 kVA:

https://www.sitebox.ltd.uk/lumer-33...MIp6-Pz7qu4QIV4ZPtCh2LUgCmEAQYAyABEgKBI_D_BwE
All you need is a 110V-to-US adapter, made by attaching a yellow 110V male plug to a US trailing socket. As for the spikes, how about a surge protector strip?

 

[anorlunda]

The 220v version from Australia or Europe has a pricetag of $300 more + shipping.

Oh dear, you won't like this. It may cost you more than $300 to step down the voltage and protect against spikes. And now you have the risk of spending more money for a solution that does not meet your needs. Is there any chance of returning it for a refund?

However, even if you bought the 220V version, it would still need spike protection.

Surge protectors may or may not work. What kind of spikes do you get, lightning strikes, or high voltages lasting several seconds?

I found these cautions in the ad for a step down transformer.

• MAX - 3000 Watt for 30 Mins Use. For continuous use: 1500W. Make sure you multiply x2 the wattage of your item and get a transformer bigger than that
• WARNING: We do not recommend for high wattage heat producing items such as Coffee Maker, Expresso Machine, Toaster & Welding Equipment ETC

Since both the 220V and 110V versions may be vulnerable to those spikes, the best solution for you may be a gasoline portable generator for the oven and no power grid connection.

Most of us here on PF live in western countries that do not have such poor quality electric power, so our experience and advice is limited.

 

[Guineafowl]

I guess the OP has several problems:

1: Voltage. That site transformer should cope nicely with that, as it’s a beefy item rated for use with power tools with motors that take a gulp of inrush current, much like a microwave transformer.

2: Spikes. Universal answer - what do others in your new area use? Use that before the transformer.


3. Frequency. Your oven is 60Hz rated, but I bet it’s a 50Hz supply where you are. The turntable may move slower, the element should be fine, the microwave transformer might get a bit hotter. Hopefully the timer is not referenced to the mains frequency...

No easy answer to this, other than @anorlunda ’s above (generator with selectable frequency). The previous owner of my house was from the US, and ran a lot of his US appliances and tools from a 110V site transformer. As long as the wiring to the power socket is suitably rated and fuse/breaker-protected you should be fine. In the UK, all appliance plugs have their own fuse, so a fault will pop the fuse rather than set the lead on fire.

 

[GoatGuy]

Sometimes it pays to figure out what is in your microwave... We have an Amana brand (1990s),which inside has a large transformer (DANGER! DANGER!) and a set of primary wires that are hooked in series for 220 V operation, but in parallel for 110 V operation. With a screwdriver, you can re-arrange the series/parallel circuit. IF you get lucky, you'll need no step-down transformer at all. I would advise against using an AVR though. The high voltage transformer of the microwave is remarkably spike-susceptible. AVRs generate spikes. Lots of them.

 

[jim hardy]

At that price it's probably an inverter microwave.
If so, the magnetron's high voltage supply would likely run from 220
but 220 would wreck the interior lamp, fan, and computer board.

It is worth a careful reading of the instruction book, and an inspection as mentioned in the post above, to see if it's indeed provided with a dual voltage option.

old jim

 

[anorlunda]

This thread has veered into very dangerous territory. I will scrub it of all posts about dangerous practices.

@Alvs, please discontinue hacking of the mains wiring. You or your family may be hurt.

Thread closed.