0
\$\begingroup\$

I have tried to use speed control for vacuum cleaner like below (2000W):

enter image description here

I have tried this circuit with two different control methods for the TRIAC (BTA24 -24A):

  1. Arduino base by MOC3063
  2. DIAC for TRIAC control method.

I have a pin header for switching between above input, which is not shown in the circuit schematic below (the values are selected based on photo below):

enter image description here

When I tested the above circuit with my drill (650W,) it worked fine but when I used it with the vacuum cleaner, it started to work at lower speed than normal, and can not be controlled by the TRIAC. When I tested the TRIAC according to these instructions, I found that MT1 and MT2 are short circuit, so the TRIAC is burned.

Why did it burn out? Is there an error in the schematic like in the list below?

  1. Need to increase the MOC3063 to MT1 resistance to 500kohm similar to this schematic:

enter image description here

  1. Need to add more capacitance between the DIAC (DB3) and resistor (R1), similar to this schematic:

enter image description here

  1. The load snubber circuit is not selected correctly and needs some inductor coil similar to this schematic:

enter image description here

Update:

About the heatsink:

The test duration was around one or two seconds, the TRIAC would not be so hot, also, I have added some simple heat sink on it (a piece of home key metal as heatsink), which is removed during the TRIAC burning test and is not shown in the uploaded photo.

My TRIAC IC was BTA24 which i have dome a mistake in question as said BTA41 Instead of it (Fixed now!).

\$\endgroup\$

2 Answers 2

1
\$\begingroup\$

2000W on 200V power is 10A. If your power is 100V it's 20A!

You need to have a large heatsink or a smaller one with a fan for the triac to operate for long. It will be dissipating around 10W/20W. Without a heatsink at TO-220 can safely dissipate less than a watt.

\$\endgroup\$
1
  • \$\begingroup\$ The test duration was around one or two second which the Triac would not be so hot, also, i have added some simple heat sink on it ( one piece of home key metal as heat-sink) \$\endgroup\$ Jan 10, 2021 at 22:32
1
\$\begingroup\$

A drill motor will be a "Universal Motor" that is designed to operate on a variable voltage, as you would get from a triac. The vacuum may have a small induction motor and most single phase induction motors have starting capacitors, the charging current of the starting capacitor can look like a short circuit to the triac and the chopped waveform of the triac causes the capacitor to heat up and fail. It's usually a race to destruction of one or the other when you attempt to use triac speed control in single phase AC motors.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.