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Does it exist an AC to AC converter in small package for converting 220v to 110v?

SparkyChem

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Hello. I have an appliance that id like to install on the wall on my bedroom. Its a broan exhaust fan. The unit only operates using 110v and my system provides 220v. I have been looking for ways to solve my problem but the suggestions do not apply to my case. These include.

Changing the double pole 220v to a 110v single pole breaker in the panel. I cant do that because this appartment has a simple wiring and there are not two hot wires and a neutral and ground. Just one hot and one neutral.

Trying to use an adapter or converter. This solution does not apply to me because the intended appliance doesnt come with a plug and the connection and wiring must be all hidden in the electrical wall outlet box.

Trying to use a transformer. The same as above. The ones i could find are bulkier and cannot be installed on the outlet box.

Trying to find a din rail ac transformer and installing it on the electrical pannel and enabling my bedroom to have 110v outlets and current. I triend to find such but i couldnt find any. Looked on siemens. GE. Panasonic catalogs but the only ac transformers they have are for low voltages around 24v.

Trying to look for a fan which does operate on 220v instead of 110v. Well why would i be posting this question if i had given up? I just cant find an exhaust of 220v with the thickness and characteristics of the unit i intend to install. It must be a broan model.

The other option was. Does it exist a circuit or an AC to AC chip that is small enough to convert 220v to 110v and provide 5amps? It doesnt need to be that small but as long it could fit in an empty outlet box which i happen to have available, that would be enough.

Can somebody help me please?
 

FvM

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A 1000VA 220 to 110 auto transformer is by far the cheapest solution. An electronic inverter can perform the job in principle, but not much smaller and more expensive.

Did you consider to get a 220V exhaust fan?
 

kripacharya

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110Vac at 5 amps means 550 watts or 0.55Kw, which seems excessively high for a room exhaust. Are you sure about the 5 amps requirement ? If on cross-checking you find it's a lower amps/ watts then maybe you can find a suitably small transformer.
 

Easy peasy

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an auto - Tx is half the weight approx as you likely don't need isolation - if you get one on a toroid and heatsink the two sides - this will work and be in the order of 100x100x100mm... 60Hz I presume ...
 

FvM

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Moderators have deleted a number of posts from this thread which didn't contribute to solve the original question.
 

kripacharya

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Moderators have deleted a number of posts from this thread which didn't contribute to solve the original question.
thank you. It was needed.

- - - Updated - - -

an auto - Tx is half the weight approx as you likely don't need isolation - if you get one on a toroid and heatsink the two sides - this will work and be in the order of 100x100x100mm... 60Hz I presume ...
Surely OP will be happy to get details of this "auto-tx". I am sure the OP will be very thankful.

Which toroid core type are you recommending ? What size/ specifications ? What source can he use to obtain the same ? In Peru ? How many turns of wire are required ? What gauge of wire ? Any other tips and hints ? Why is this heatsink required ? What size ? What material ? Will it require forced cooling ?

10cm x 10cm x 10cm is quite large. Can you not get it smaller than that ? Does this mean that toroid is >= 8cm in diameter ???
 

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Toroid transformer is an option if you want a smaller solution, the OP might consider it or refer to a classical EI core design. It's also a good question if the load is actually 550 VA (not 1000VA as previously written). No need to elaborate design details before the requirements have been clarified.
 

summitville

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What if you installed a wall mounted electronic 230 Volt Variable Speed Fan Controller inside the J-box?
And then permanently set the output to 50% Power?
Something like this ...

SPEED_CONTROLLER

In this model, I do not like that "OFF" goes directly to "HIGH", instead of "OFF" to "LOW".
Does the fan have a built-in On/Off switch?
At some low setting of the fan speed controller, the 115 Volt fan should be happy ( ie motor is not too hot )
Verify that the speed controller that you purchase, is compatible with the TYPE of motor inside the fan.
 

kripacharya

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Speed controller as suggested by Summitville typically work by varying the firing angle of a Thyristor. While this provides reduced RMS voltage, it is quite stressful on the motors. Peak voltage of 220x1.414 will still appear on the output, and the sharp switch-on/off often cause fan motors to emit a buzzing sound.
 

summitville

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If you know, then tell us exactly what percentage of the normal-life will be lost be using a Solid State Speed controller set to 50% power?
 

BradtheRad

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I've seen advice telling to derate (reduce) power to an inductive load rated for 60 Hz, when you run it at 50 Hz. The reason is because an inductor admits greater current at the slower frequency. The risk is overheating and burning.
I'm pretty sure the risk is reduced when the windings contain some amount of ohmic resistance (as is probably the case in your fan).
It should be okay if speed is kept low enough so motor temperature doesn't get too hot.

- - - Updated - - -

This raises the question 'What is too hot?'. I guess it's if, after several minutes of running, the housing is too hot to hold your fingers on the housing.
 

summitville

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Speed controller as suggested by Summitville typically work by varying the firing angle of a Thyristor. While this provides reduced RMS voltage, it is quite stressful on the motors. Peak voltage of 220x1.414 will still appear on the output, and the sharp switch-on/off often cause fan motors to emit a buzzing sound.
No, the turn-on phase angle, for equivalent 120 V rms, will be small enough that 220x1.414 will never be applied to the motor.
 

kripacharya

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No, the turn-on phase angle, for equivalent 120 V rms, will be small enough that 220x1.414 will never be applied to the motor.
Interesting observation. Could you share your calculation methods please ?
 

kripacharya

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My intuition says that to achieve half the Vrms, we should have a phase angle close to 90deg. Which means the peak will at least be close to 220x1.414.
 

andre_teprom

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My intuition says that to achieve half the Vrms, we should have a phase angle close to 90deg. Which means the peak will at least be close to 220x1.414.
The maximum peak voltage dimmed from 220vac equivalent to the peak of 110vac should be considered regardless of the rms voltage delivered to the fan.

The half voltage is obtained with a firing angle of exactly -30° (=arcsin(½)), at least in theory.
 

kripacharya

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That makes sense in so far as peak voltage is not violated. But won't this firing angle result in lower Vrms, and hence lower fan speed from what is expected? That's the point being made here. If OP is OK with that, then good.

Only thing left to consider is the vibrations caused due to fast transients every half cycle.
 

andre_teprom

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won't this firing angle result in lower Vrms, and hence lower fan speed from what is expected?
That's the point being made here.
No, this was not the point, but rather to advice OP about the correct value of the absolute maximum firing angle to be adopted in the design of the control circuit, just that.

BTW, some fans have internal electronic circuitry, so what matters for one device could not matter for another one, therefore there is not an optimal approach to solve this problem unless having more details on the fan to be dimmed.
 

kripacharya

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OP just wants a pick and fit solution. He's not looking to design or make anything. Referred Broan fans are most probably shaded pole induction motors without any additional electronics.

Best suggestion so far is toroidal autotransformer. But without detailed design information the suggestion is useless.
 

Easy peasy

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Conduction angle is in fact about 65 degrees i.e. the first, or last 65 degrees of each half cycle, if you want 110V rms from 230Vrms

- - - Updated - - -

SCR firing.JPG per the above ...
 

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