# Clarity please? Built a timer controlled outlet out of old Microwave. Adding a fan now. Question on fan?

#### Tonyr1084

Joined Sep 24, 2015
5,868
OK, on THIS thread I posted a completed project. Today I decided to add in an extra outlet to control a fan. It's working the way it's supposed to. BUT here's the problem: I have a shade pole motor fan for my work bench. I don't use it much because it's somewhat stronger than I care for. Knowing that this project can control an extra light or extra fan - I plugged this shade pole motor into it. When plugged into the fan port it will run at full power on high. But on low it stalls out and does nothing. Tried it on the "Light" circuit but there on High the fan spins up and down and up and down repeatedly, never attaining a full running speed. When the light is switched to low the motor stops all together. In either case it doesn't work. So I tried a regular 3 speed fan. The light circuit will run the fan when the light is on High. But when switched to Low the fan barely spins at all. It doesn't matter which speed I set the fan on (Low, Med or High on the column) when the light circuit is set to Low the fan barely spins. Obviously it has to do with what sort of motor I am using. That's where you guys come in:

The Light Circuit is controlled by two relays and a diode. It would seem that on high one relay applies full power to the lights. On Low the light circuit applies full voltage through a single diode (half wave clipped). I've plugged a light into the circuit and it does exactly what it's supposed to do - change the light from low to high and off. That's nice. But I don't want to control lights, I want to control a fan. So what kind of fan is recommended? The one that came out of the oven ? ? ? That's a pretty large squirrel cage fan and moves too much air, even on low. So I'm looking for options.

I'm waiting for a picture I took with my phone, sent via e-mail to my e-mail address. iPhone 11 takes a long time to send a picture. Will post when I get it.

#### Tonyr1084

Joined Sep 24, 2015
5,868
Picture came in.

In the upper right side there's a black wire that can be moved from L to F (Light to Fan). The light circuit is two relays and a diode. The fan is controlled at the bottom right corner of the control board. Let me know if you want a closeup of something; but the fan is controlled by a three leg device.

#### ThePanMan

Joined Mar 13, 2020
62
Neat! Maybe a universal motor will work the way you want. But it might depend on the circuit that is controlling the motor speed.

#### KeithWalker

Joined Jul 10, 2017
1,691
You need a triac type of controller to vary the speed of a shaded pole motor. Most AC fans use this type of motor. Some have several shading rings or windings to switch the speed.
Any AC brushed motor with a field winding would work with a diode to reduce the speed. A DC brushed motor on a bridge rectifier would work too.
Regards
Keith

#### Alec_t

Joined Sep 17, 2013
12,009
Any AC brushed motor with a field winding would work with a diode to reduce the speed.
Be wary of trying that. If the winding saturates because it is carrying DC it can burn out. Ask me how I know!

#### Tonyr1084

Joined Sep 24, 2015
5,868
I'm not looking to modify anything. Just wanting to plug and play. Don't want a big fan either. Something small, just to move some air across my workstation. I don't have solder smoke extraction, and I'm fairly certain many of you have experienced the same thing, that in a still room smoke from soldering finds its way into your face. I don't do a lot of soldering, and the fan isn't necessarily for that purpose.

I have two options: I can move the wire from the fan control circuit to the light control circuit. One way or another I want to run a small fan on low or high.

#### Tonyr1084

Joined Sep 24, 2015
5,868
I thought I commented about solving my problem. I have the MWO Fan wired and working (when plugged into standard outlet). Confident it would work, I plugged it into my MWO Controller. But I think I may have hurt it yesterday. Today nothing will work on that circuit. There's a BT139 Triac and a MOC 3023 (six lead) chip. Probably an opto. Today's project will be to get this back in operation.

So how does one check a Triac?

#### KeithWalker

Joined Jul 10, 2017
1,691
The BT139 only needs about 1.2 volts to trigger it so you can test it with your multimeter:
Swtch to diode test and connect the test leads across the triac with the positive lead to MT2 and negative to MT1. The meter should show open circuit.
Short the gate to MT2 and the triac should turn on, giving a forward diode measurement.
Switch the leads over and repeat the test for the other half of the triac, again shorting the gate to MT2.
That is not a very thorough test but it will quickly check the functionality of it.
Regards,
Keith

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#### Tonyr1084

Joined Sep 24, 2015
5,868
Here's the circuit. The image has been flipped to represent the component side view. The board is single layer (bottom) but the picture is of the bottom. The hand drawn components are on the component side as if you were looking through the board. Much of the circuit in the picture is critical to other functions. The two leads leading away from the Opto are controlled by programming and the Hot and Neutral lines doing down go to the transformer.

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#### MisterBill2

Joined Jan 23, 2018
8,486
What you have is a standard microwave oven timer system. For an oven the lower power setting is done vial low frequency pulse-with modulation, with the off-on rate being a few seconds. That is how they reduce the power, by reducing the average power. I would use a regular incandescent light to check and see if it is a circuit fault or a motor fault.

#### Tonyr1084

Joined Sep 24, 2015
5,868
Thanks Bill. But that part is not an issue. I'm only using the MOT control to switch an outlet on and off. I've added another outlet and connecting it to the fan circuit (BT139-600 controlled). Last night I did some testing with various fans. Seems I blew out the triac. Looking for replacement now. Would scrap one out of something if I could find one. So far I've conjured up a BTB06 which is a 6A triac whereas the 139 is a 16A.

The reduced power to the MOT is of a frequency WAY too low for what I want. On for five seconds, off for five seconds. That would not regulate the speed of a fan at all.

Now to find a good supplier. Digikey wants $7.49 for 10 of them and a shipping cost of either$4.99 or \$8.99, depending on the shipping weight. Which they can not tell me via chat. So I'm looking for alternate suppliers. Maybe Mouser? Any suggestions?

#### Tonyr1084

Joined Sep 24, 2015
5,868
The BT139 only needs about 1.2 volts to trigger it so you can test it with your multimeter:
Swtch to diode test and connect the test leads across the triac with the positive lead to MT2 and negative to MT1. The meter should show open circuit.
Short the gate to MT2 and the triac should turn on, giving a forward diode measurement.
Switch the leads over and repeat the test for the other half of the triac, again shorting the gate to MT2.
That is not a very thorough test but it will quickly check the functionality of it.
Regards,
Keith
Did that. Got 61 to 62 mV each way with MT2 shorted to Gate. Used to seeing in diode test mode having somewhere around 470mV readings. While testing MT1 to Gate or MT2 to Gate, positive or negative, I got the same readings.

#### KeithWalker

Joined Jul 10, 2017
1,691
It switched so I guess you didn't manage to destroy it. Good luck.
Keith

#### MisterBill2

Joined Jan 23, 2018
8,486
It switched so I guess you didn't manage to destroy it. Good luck.
Keith
OK, the triac is OK, now check the fuse for that part of the circuit and also try it with a light bulb to see if i works with a resistive load, or not.

#### Tonyr1084

Joined Sep 24, 2015
5,868
No fuse. Light bulb doesn't work either.

Looks like I forgot to label that capacitor between hot and the opto (pin 4). Labeled
0.1 µF (x2)
AC 275 V

Don't know what the (x2) means. But that's basically what's labeled.

Had power failure. One of the two lines from the transformer on the pole in my back yard burned through completely. The other line was pretty crispy too. Neutral was in good condition but the power crew replaced all three wires. Plans are in the pipe to put another transformer up north of my house. Right now there's 14 houses on a single transformer. Power Co. wants to reduce the load by adding another "tub" as they call transformers.

Will get back to troubleshooting this Frankenstein of mine.

#### MisterBill2

Joined Jan 23, 2018
8,486
No fuse. Light bulb doesn't work either.

Looks like I forgot to label that capacitor between hot and the opto (pin 4). Labeled
0.1 µF (x2)
AC 275 V

Don't know what the (x2) means. But that's basically what's labeled.

Had power failure. One of the two lines from the transformer on the pole in my back yard burned through completely. The other line was pretty crispy too. Neutral was in good condition but the power crew replaced all three wires. Plans are in the pipe to put another transformer up north of my house. Right now there's 14 houses on a single transformer. Power Co. wants to reduce the load by adding another "tub" as they call transformers.

Will get back to troubleshooting this Frankenstein of mine.
Usually that (x2) means that you have a 3-leaded component that is a dual capacitor package with one common connection. Mostly those are used as bypass capacitors. But caution is needed in replacing because there are also bypass caps that have one lead looped through, which is done to reduce the series resistance in the bypassing.

Was it a wire from the pole to your house that burned through? Or from pole to pole?

#### Tonyr1084

Joined Sep 24, 2015
5,868
Was it a wire from the pole to your house that burned through? Or from pole to pole?

#### Tonyr1084

Joined Sep 24, 2015
5,868
Usually that (x2) means that you have a 3-leaded component that is a dual capacitor package with one common connection.
Only has two leads coming through the board. Doesn't appear to have a lead that may have been trimmed off.

#### Tonyr1084

Joined Sep 24, 2015
5,868
In an effort to better understand what's going on - made a schematic.