how to run 200vac induction motor with 230vac supply?

[circuit_freak]

hi guys,

i bought a ac motor from japan, supply voltage is 200vac but my country is 230vac.
Motor runs when i supply 230vac but it become very hot after 10min so i believe the supply voltage is over its spec.

possible to reduce heat if i add a SSR with kickback diode between contact and run the motor with 50% duty cycle, 500Hz?
any idea people?

thanks in advance.

 

[BradtheRad]

A triac is made for this job.

I had to google SSR to find out you're talking about a solid state relay. I suspect you were prepared to undertake the design and construction of a complicated PWM driver circuit, having forgotten about triacs momentarily, and that you need no further advice.

As for kickback (or snubber) diodes I don't know how necessary it will be with a triac. It does not switch off the motor coil suddenly.

 

[circuit_freak]

ok, let try an easy way.
instead of complicated circuit, i wonder is there any 230 to 200 transformer or 230 to two 100 transformer?
anyone experience this before?
thanks

 

[BradtheRad]

In that case an autotransformer is what you want. The kind with multiple taps.

Autotransformer - Wikipedia, the free encyclopedia

These are less expensive than a transformer.

You would need one with an adequate watt rating. Maybe 100% more to handle surges.

 

[jpanhalt]

Is the motor designed for 50 Hz or 60 Hz? What is your mains frequency?

John

 

[circuit_freak]

Hi,

jpanhalt - this motor is able to cable both frequency 50hz & 60hz. my main frequency is 50hz


BradtheRad - any recommend brand for my info? i couldnt get it from digikey mouser e14 & rs

base on datasheet this induction motor current consumption is around 0.15A only

thanks~

 

[BradtheRad]

Your current draw is low enough that you can use a variac. Works pretty much the same as an autoformer. It will have to be rated for 220V. You don't need a current rating greater than 1/3 or 1/2 A. You might find a used one cheap on Ebay.

There do not seem to be autoformers made for that low wattage and 230V AC.

Another method: It may be possible to remove windings from an isolation transformer. Again it would need to be for 230 V. (Although I'm not absolutely sure you couldn't use one for 120. To a large extent current through the primary depends on how much current you're drawing from the secondary, and you're not drawing a lot.)

Consider using a triac. One of my earliest projects was an AC fan speed control. I followed the simple layout printed on the back of the Radio Shack card. Only a few components. I just soldered them all together. It worked. I didn't use a circuit board or a heatsink.

 

[BradtheRad]

Another possibility. Add an inductor inline. The idea is to choke current flow by about 13 percent. It should drop 30VAC.

Since your motor is rated .15 A at 200VAC, it has a net impedance of 1333 ohms.

You want to add another 200 ohms reactance.

(You probably are aware already that increasing ohmic resistance by itself will not do the job.)

Consulting a calculator for inductor reactance at 50 Hz. It shows that 0.65 Henry will do the trick.

The formula is inductance only. Your choke will have some resistance, probably a few ohms. However that won't impact your motor performance.

The choke needs to be rated to handle the current flow without overheating.

I'm including this idea in case you have a choke or two sitting around the house. Or you could use one winding of a transformer to act as a choke.

 

[qayyoum]

hi
oh...my dear simply use fan dimar .........enjoye

 

[BradtheRad]

simply use fan dimar .........enjoye

Yes. Nothing wrong with this either.

It should be the dimmer that is made for a motor. A light dimmer may not be suitable. (Though puzzling to me since the triac control worked with my fan.)

Here's a website with more info (fancollectors.org):

Slowing Fans

 

[E Kafeman]

Assume it is an asynchronous induction motor (brush-less) with integrated cooling fan. If it becomes too hot, is it overloaded? Measure current.
Other reasons can be partly burnt windings, if capacitors are used for start-up and phase correction can they be dry or shortcut. Unusual smell and sound are indicating these types of errors.
An induction motor during same load have almost same heat-loss at 200 or 230 Volt AC.
Unloaded is heat-loss ~1.32 times higher (230/200)². As this is unloaded and with max rpm at cooling fan should it not be any problem.
Max rpm is mainly depending on frequency and number of poles, not voltage. Magnetic saturation increases heat which can be caused by over-voltage, but is not likely in this case.
I do not recommend to use a motor beyond its marking plate. Isolation is for example a security aspect that is voltage depending. Windings are designed for a certain max current and overload or start can cause too heavy peak current and reduced efficiency.
Voltage can vary quite wide for this type of motor while it can maintain almost same performance. Previously could you find motor-plates saying 220VAC +/- 10%. Nowadays is it rather common with this type of markings:
AJVS 1-phase-motor-208-240-v-50-60-Hz
Main data for this motor remains similar for 200-240 V (± 5 %) 50 Hz or even when switching from 50-60Hz, except that rpm increases.

Using a lamp dimmer for controlling an inductive engine is a way to increase heat in the coils of the engine and in worst case burn some windings. For a certain RPM and load is a average amount of power needed. A dimmer cuts out a part of every 50 Hz period which increases peak current during remaining time, resulting in higher peak current and increased resistive losses in the motor. Also magnetic saturation is a likely problem when current goes 200% above what the motor is designed for, producing a lot of heat.
For an inductive motor, the only simple way I know about to adjust heat dissipation (optimize efficiency) for a certain load is to use a frequency inverter.
Avoid unstable serial loads if you not is really sure about what you are doing. Serial resistors occurs in some rare cases to reduce start current in elevators, both parallel and serial capacitors are common as phase correctors but avoid serial inductors as it increases inductive load and can cause arcs over mains switch when powering off. At 0.65H/1A can you assume mains switch as something for onetime use, including parts of surrounding wall .
If market-plate says your voltage is too high, and you want to reduce it for security reasons, use a transformer. As it is a small electric motor is a transformer rather cheap.
These types of transformers can be used **broken link removed**. You use only primary winding.

If it is a brush motor can a lamp dimmer be used to adjust torque, but back EMK can kill the dimmer. That is the reason for special motor-dimmers, which have some protection against back-EMK.

 

[Raza]

Hi,
Here is the simplest circuit to control motor speed. Even you can assemble yourself with just a few dollars cost.