300 watt motor circuit problem

[ali-meiyahi]

Hi... am have a 300 watt motor connected by an electric circuit as shown .. source is 220 v 50 hz... but when closing the circuit resistance (R2) burn.. this is my problem if can you help me to solve it.... thanks.

**broken link removed**

 

[kripacharya]

Your resistor power rating should be at least 1 watt or more, if your motor is working properly.
The normal max I-rms through the resistor should be ( 220/ 300 =) 0.73 amps

However, if your motor is NOT rotating, then there will be heavy current through R2, and it will overheat. This is very possible at startup time, so you should either remove R2, or possibly use an even higher power rating - say 5w resistor.

 

[tpetar]

R2 cant handle that current.

What you try to make some kind of soft start for motor?

 

[ali-meiyahi]

i still suffering this problem after replacing R2 by higher power rating.. also the motor is rotating and there is no problem with it's rotate.

 

[kripacharya]

what power rating have you put in now ? Please specify, or post a picture.

Its not clear how your motor is working if the R2 is burning up. Does it short out when it burns ?

 

[pplus]

Check D1-D4. If R2 by higher power rating burn. I think start current of your motor greater then 2A.

 

[ali-meiyahi]

thanks for you interesting.. but i still suffering this problem till now although i did all your suggestions.
i ask now a bout designing a circuit can operate a 300 watt DC motor if the source is 220 v and overlooking the above circuit..
if you want help me.. plz

notice: the resistance of motor's coil is between 30 - 150 ohm

 

[rfredel]

Hello ali-meiyahi,

please tell, what is write on the nameplate of the motor. What voltage, what current, what type of Motor (Series - or Shunt winding)?

the resistance of motor's coil is between 30 - 150 ohm

That can not be! The resistance of the windings are fix values.

Regards

Rainer

 

[chuckey]

I would check the diode bridge, its likely that one diode has gone short circuit. there should be a small capacitor across the diode bridge or motor, say 47 NF@ 350V, to protect the bridge against sparking from the motors brushes.
Frank

 

[rfredel]

Hello Frank,

the small capacitor is ok, but in my opinion the voltage is to low. I would take 630V, because the peak value of the DC voltage is 312V.

Regards

Rainer

 

[ali-meiyahi]

motor power is 300 watt, voltage is 200 v DC, and the current is 1.5 am.
when i putting ohmmeter on the ends of motor's coil the ohmmeter reading between 30 - 150 ohm every one i rotating motor by my hand

 

[BradtheRad]

when i putting ohmmeter on the ends of motor's coil and rotating it by my hand the ohmmeter reading between 30 - 150 ohm

The motor is generating juice when you rotate it. This will throw off the ohm reading.

Leave the motor stationary when checking its ohm reading. This will let you calculate the maximum amperes that must be carried. You'll have an idea what should be the ratings of the components.