details of HEF4752 - Electrician Talk - Professional Electrical Contractors Forum

onlyvinod56 · 03-10-2009, 12:44 PM

Hi every one,
this is my first post in this forum.
Iam designing a sinusoidal 3 phase PWM inverter whose output frequency can be varied in proportion to the speed of an induction motor. I will convert the spped into a voltage. That voltage can be used to control the frequency of the inverter. I came across the IC HEF 4752. There are certain pins like FCT, OCT, RCT & VCT.

Iam not understing the use of that pins. Can i control the inverter frequency by varying the frequency at the FCT pin?

In few circuits NE566 is connected to FCT pin. In some circuits CD4066 is used.

Please clear my doubt. How can i go ahead here?

p_logix · 03-10-2009, 07:31 PM

Quote:

Originally Posted by onlyvinod56

Hi every one,
this is my first post in this forum.
Iam designing a sinusoidal 3 phase PWM inverter whose output frequency can be varied in proportion to the speed of an induction motor. I will convert the spped into a voltage. That voltage can be used to control the frequency of the inverter. I came across the IC HEF 4752. There are certain pins like FCT, OCT, RCT & VCT.

Iam not understing the use of that pins. Can i control the inverter frequency by varying the frequency at the FCT pin?

In this PWM inverter those are four clock inputs supplied from NE 566. The clock input FCT, controls the inverter output frequency, the (motor speed). The output frequency of the inverter can be controlled

from 0 to 72 Hz by varying frequency of the FCT pin.

My gosh building your own VFD?

Anyway I got a little interested and found the drawing and some additional information for you that explains using the FCT pin for varying frequency, it should be everything you need good luck!

p_logix

PDF]
Speed control of three phase induction motor using single phase ...http://www.icgst.com/acse/Volume6/Issue3/P1110615003.pdf