Need Help!- HF Model # 39743 or Bolton AT-125 Re-Wiring Help...

[blkbagger]

I have an AT125 Mini Multipurpose machine, same as Harbor Freight 39743, I had to replace a switch in the machine due to a burnt connector, I found the cause was some bad wiring, insulation was cut through, I was a dummy and did not take photos of everything before disconnecting and disassembling the wiring harness, I am having a problem with the section of wiring that contains the DPDT reversing switch...

The motor is a single phase cap start motor with 4 leads, I am assuming a start winding and a run winding from the schematic... My problem is identifying the correct wiring to the DPDT switch from the motor wiring harness... See enclosed photos... In the photo of the DPDT switch, I have cut or desoldered the four leads from the motor and the two leads from the magnetic safety switch, this is where I messed up(not taking a photo)

Any help would be appreciated, if someone has this machine, if you can take a look at the wiring of the reversing switch and make a color coded diagram it would be most appreciated... The colors are different than the printed scematic, but only on one side of the motor, everything else matches the schematic...

[neilw20]

You don't show a full picture, but it looks like 2 wires to the switch and 2 loop wires.
That being correct, the middle 2 connections of the switch go to the motor as per the diagram, green/yellow, and green.
The two black wires from the switch got to the brown and black of the motor.
If the motor runs the wrong way according to the switch, turn the switch around in the panel.
Make sure you don't change direction while the motor is running.

[blkbagger]

Thank you for the response, anything else I can show you to make certain this is correct I can provide photos of, there is also the external capacitor that is supposed to be connected to the black wire out from the direction switch, then back into the motor diagram, I will post photos of the original setup, there is a six position modular connector between the switch harness and the motor harness, there is a loopback on two positions on the switch side, on the motor side, the two leads from the capacitor where there along with the four leads from the motor...

I hope I am not confusing you with this explanation, I will attach photos as I need to make certain this is correct, I have spent a lot of time working on this rebuild and want it to be good to go...

I will pull the electrics and photograph what I have... All I remember is this motor has a lot of grunt and works well with my micro lathe... It is worth the effort to me...

Thanks again for your assistance...

Ken

[john_100]

Hi Ken

will this do ?

John

[blkbagger]

That might help, I made the mistake of not leaving enough wire with insulation colors on the DPDT switch and not taking macro photos of the original setup(dummy me, something I always do when disassembling)

I'm prepping some photos so you can see the nightmare the stock setup is, the confusion comes from the reverse switch, the cap and the loopback in the wiring harness... Your drawings may help quite a bit, I think I understand what is happening here, only the run winding is being reversed??? That's what confuses me, I would think the start winding would be needed after the motor has stopped, the reverse switch toggled and restarted the starter windings would need to be initiated to start up in the reversed direction??? I must be missing something...

Here's some photos of what I have to work with, there is a safety switch on the change gear door, there is a magnetic safety switch, then the mess of the reversing circuit...

Ken

[blkbagger]

I need to get my micro lathe done so I can move on to finishing up my hybrid CNC micro mill...

it features replaceable spindle cartridges, the stock X-1 micro mill head, a genuine Sherline spindle cartridge with high speed DC drive and a Dremel Tool spindle for really high speed use of small cutters...

Here's a couple photos of my CNC mill conversion...


Ken

[Al_The_Man]

Originally Posted by blkbagger T. Your drawings may help quite a bit, I think I understand what is happening here, only the run winding is being reversed??? That's what confuses me, I would think the start winding would be needed after the motor has stopped, the reverse switch toggled and restarted the starter windings would need to be initiated to start up in the reversed direction??? I must be missing something...

It does not matter which is reversed as long as one is reversed WRT the other.
According to the original diagram they are reversing the run windings only.
Al.

[blkbagger]

You guys are great, I sincerely appreciate all the assistance, I will wire this up per the diagram and put a meter to it, fingers crossed, I want to get my lathe running again...

If I have any problems I will ask for additional help...

The mfg made a mistake and the color coding of the wires is incorrect compared to what I have, the motor has the green and green/yellow, but the black and brown are replaced with red and blue in my motor... I will substitute, one for one and wire it up...

I will check polarity with the meter and a straight through connection in place of the capacitor, I would rather confirm correct wiring without power applied... When the switch is thrown and tested with my meter which pair should be reversed ?

Again thanks for all the tips and help, it is sincerely appreciated...

[Al_The_Man]

The ground conductor should be easy to check to motor frame.
Check continuity between red & blue to see if they are actually one winding.
If the motor runs Rev instead of Fwd at power up, swap conductors on any one pair of windings.
Not sure why they use green/yellow as a conductor which is ground in most parts of the world, but that is China I guess!!
Al.

[blkbagger]

Originally Posted by Al_The_Man The ground conductor should be easy to check to motor frame. Check continuity between red & blue to see if they are actually one winding. Not sure why they use green/yellow as a conductor which is ground in most parts of the world, but that is China I guess!! Al.

I just checked with my meter to verify the winding, I've got continuity between the blue & red wires, is there a way to determine which equates to black and which equates to brown??? Or does it matter???

And again, thank you for the tip... I have a clue about electronics, but not a whole lot of knowledge about AC motors, different types etc...

Ken

[Al_The_Man]

See edit in my last post.
Al.

[john_100]

Hi

Al has made a good point

check the motor is wired as expected and the green/yellow wire is not connected to the
motor case

I have revised the wiring to the expected new colours
but at the moment , can not be 100% sure of how to check which winding is which

I think for a capacitor start motor
the start winding connected to the capacitor has the lowest resistance
and the switch opens at about 75% of he running speed

John