# Wiring a multi-speed motor from a tower fan

I am trying to fix a tower fan from a friend. He found out that the motor was working, but something on the circuit board wasn't. He then took apart the board from the motor without remembering which wire of the motor connected to pads on the circuit board. Now I am trying to find out how this single-phase AC motor works by measuring the resistances across the wires. I did this and found out that some of the wires have some resistance between them (from which I conclude these are the common and speed select wires). There are also two wires (grey and brown) which have infinite resistance to the rest of the wires, but between them have zero resistance. In total I have 7 wires and I will give the resistances down below. Can someone help me with finding out what every wire is supposed to connect to?

I also have a capacitor which was connected before to the circuit board (very large cap). I also already tried to look the motor up on google (Shanhu shm-40), but I can not find anything that looks like a wiring diagram or something like that.

Grey-Brown --> 0 ohms

The other 5 wires seem to be connected in the following way (with resistance from white to black being 1279 ohms): White-->Blue-->Yellow-->Red-->Black

The following resistances are in between these connections (they add up pretty close to the total of 1279 ohms). White-Blue --> 332 ohms Blue-Yellow --> 174 ohms Yellow-Red --> 204 ohms Red-Black --> 594 ohms

The fact that brown/grey are not connected at all to the other wires seems very strange to me. If anyone could help me solve this problem I would be very thankful :D.

• I'm voting to close this question as off-topic because there is not enough information to work with. Sometimes this sort of problem is solved successfully, but this looks like a bigger mess than usual.
– user80875
Commented Sep 27, 2019 at 15:20
• @CharlesCowie Yep I know it is a big mess... I already searched for 3 days on the internet about these kind of motors, but I can't really find a motor that has the same color of wires coming out of it... Commented Sep 27, 2019 at 15:24
• Need a product number and a datasheet Commented Sep 27, 2019 at 16:29
• @VoltageSpike The motor itself is a Shanhu SHM-40 (I can not find a datasheet). The tower fan is a Honeywell H0-5500RE. Commented Sep 27, 2019 at 16:33
• @CiaranLichtenberg does it have a nameplate? Commented Sep 27, 2019 at 16:34

The Shanhu SHM-40 motor is a three speed 230V motor. It has 7 wires to connect.

This is how I connected the motor after my controller board had a broken power supply for the remote control.

• Brown: Brown wire of your power cord.
• Grey: Connect to Blue, Yellow or Red to choose your speed. Ideally, with a 2A fuse.
• White: Connect to the capacitor.
• Blue: Slow Speed
• Yellow: Medium Speed
• Red: Max Speed
• Black: Blue wire of your power cord and the capacitor.
• Funny thing, I opened up my tower fan just yesterday and found your post when searching for that motor. So I reverse engineered the PCB to find out the correct connection. Commented Sep 30, 2019 at 20:47
• You sir are my hero! Thank you so much! I was so confused up untill now haha. I am going to try this, thank you for taking the time to answer my question. Commented Sep 30, 2019 at 23:48
• I actually have one more question, do you know if this motor needs a timer to prevent it from overheating? Or does the circuit board not include such a function? Commented Sep 30, 2019 at 23:52
• The circuit board has a timer. But this timer is not mandatory. It can run all day. So I believe it is fine. The motor is also cooled by the big fan. Commented Oct 1, 2019 at 18:10
• Just in case someone's here bc of a dead Honeywell H0-5500RE: Most likely the power suppy for the control unit on the top is broken (check w multimeter), Easy ghetto fix: wire any 5V power suppy into the fan's mains and solder the 5V directly on to the pcb's connector for the control unit. Commented Aug 17, 2020 at 22:52