Clever soft-start module for AC power tool motors
bigclivedotcom 14:19
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Despite them rating this module at 20A I'd suggest using it at much lower current to avoid excessive heat dissipation from the triac. In some applications it will also benefit from having its tab mounted to a heat dissipating surface.
When powered up, this unit uses phase angle control to gently ramp the output up over a few seconds. It is aimed at specific loads like power tools with universal motors (the type with carbon brushes). It should not be used with some electronic loads like switching power supplies and some motors.
The main advantages of the soft start are reduced peak starting current to avoid nuisance circuit breaker tripping, and also the greatly reduced strain on the mechanical components.
Note that there is no RF noise filtering, so some radio noise may occur locally during the initial ramp up.
The circuitry is very clever. It uses a microcontroller to drive a triac and uses a simple zero crossing point detection circuit for three functions - triac trigger timing, to reset as soon as the power is removed and also to control a simple resistive dropper so that it is only active for a short part of the sine wave near the zero crossing point.
It's possible that adding an external snubber network (100nF capacitor in series with a 100 ohm resistor) may give better protection to the triac.
The triac is from the BTA series, so its mounting tab is isolated, but note that some triacs have live heatsink tabs. The suffix B usually indicates gate sensitivity.
As usual,, this technical delight came from AliExpress (not a sponsor). Here's an affiliate link to the item. Note that it will probably pop up in a bundle deal.
https://s.click.aliexpress.com/e/_c4KNUv5T
The price varies wildly between about £1.30 to £3.50, so shop about.
If you enjoy my videos, supporting the channel on Patreon helps keep it independent of YouTube's quirks, avoids intrusive mid-video adverts, gives early access, bonus footage and regular quiet Patreon live streams.
https://www.patreon.com/bigclive
Alternatively, for a single coffee contribution you can use PayPal:-
https://www.paypal.com/paypalme/bigclive
#ElectronicsCreators
When powered up, this unit uses phase angle control to gently ramp the output up over a few seconds. It is aimed at specific loads like power tools with universal motors (the type with carbon brushes). It should not be used with some electronic loads like switching power supplies and some motors.
The main advantages of the soft start are reduced peak starting current to avoid nuisance circuit breaker tripping, and also the greatly reduced strain on the mechanical components.
Note that there is no RF noise filtering, so some radio noise may occur locally during the initial ramp up.
The circuitry is very clever. It uses a microcontroller to drive a triac and uses a simple zero crossing point detection circuit for three functions - triac trigger timing, to reset as soon as the power is removed and also to control a simple resistive dropper so that it is only active for a short part of the sine wave near the zero crossing point.
It's possible that adding an external snubber network (100nF capacitor in series with a 100 ohm resistor) may give better protection to the triac.
The triac is from the BTA series, so its mounting tab is isolated, but note that some triacs have live heatsink tabs. The suffix B usually indicates gate sensitivity.
As usual,, this technical delight came from AliExpress (not a sponsor). Here's an affiliate link to the item. Note that it will probably pop up in a bundle deal.
https://s.click.aliexpress.com/e/_c4KNUv5T
The price varies wildly between about £1.30 to £3.50, so shop about.
If you enjoy my videos, supporting the channel on Patreon helps keep it independent of YouTube's quirks, avoids intrusive mid-video adverts, gives early access, bonus footage and regular quiet Patreon live streams.
https://www.patreon.com/bigclive
Alternatively, for a single coffee contribution you can use PayPal:-
https://www.paypal.com/paypalme/bigclive
#ElectronicsCreators
Category (YouTube): Science & Technology
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