dc motor speed controller with pwm

[aspirecole]

im making a circuit for dc motor speed control using power mosfet IRFZ48N. when im using 12V battery, the motor is running and the mosfet is hot. when i change to 24V battery, mosfet become very hot and after a while i cant control the speed anymore due to the mosfet failure. my motor is 24V 14A 250W dc motor. i keep changing the mosfet.

 

[ALERTLINKS]

First use heat-sink with mosfet. If you are already using it, post the schematic.

 

[aspirecole]

First use heat-sink with mosfet. If you are already using it, post the schematic.

i already put a big heat sink this is my circuit

 

[ALERTLINKS]

_Use a better mosfet with low Rds-on like IRF3205. Don't use 470uF capacitor. It will cause trouble like mosfet heating. Diode is necessary in parallel to the motor as shown with dotted lines.

 

[aspirecole]

_Use a better mosfet with low Rds-on like IRF3205. Don't use 470uF capacitor. It will cause trouble like mosfet heating. Diode is necessary in parallel to the motor as shown with dotted lines.

so i should use bigger capacitor or just remove it?..because the motor produces buzzing sound.. I try with other mosfet then..thanx alot

 

[ALERTLINKS]

Remove the capacitor. Buzzing is generated due to low frequency. Increase the frequency by replacing 10nF capacitor with 1nF or change the variable resistor to below 50K or 20K.