Induction Motor Softstart Using TRIAC

Thread Starter

enggricha

Joined May 17, 2014
89

MaxHeadRoom

Joined Jul 18, 2013
28,695
If using a Triac controller I would use a burst firing method rather than phase angle control, many 1ph motors do not take to phase angle control once you get above 1/2 HP.
Burst firing turns the triac on full but for gradually increasing time on periods until full on is reached.
Max.
 

Hymie

Joined Mar 30, 2018
1,284
If you google 'soft start triac' you will get loads of circuit ideas, many much simpler than you are proposing.

https://www.google.co.uk/search?q=s...Sim-XaAhXKLsAKHXqZAYkQsAQIMA&biw=1252&bih=578

Remember that the operation of a triac is such that once the gate is turned on, the device will remain on for the remainder of the mains half cycle – switching off as the ac voltage passes 0V (unless it is a gate turn off device).
 

Thread Starter

enggricha

Joined May 17, 2014
89
I have used a pic using the Triac burst method before, for some detail on detecting the zero crossing there is Fairchild AN-3006.
Also Picmicro AN958
Max.
Thanks, these are better than the ones I came up with. Looks like TRIAC is the way to go for this application. Thanks for the validation.
 
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