Harborfreight 12x36 lathe wireing

[jdcool4]

I am having some issues with a older harbor freight lathe. And was wondering if any one has a better schematic then the one that comes in the book. I have checked grizzly but there's is wired totally different then mine.

 

[Wizard69]

I am having some issues with a older harbor freight lathe. And was wondering if any one has a better schematic then the one that comes in the book. I have checked grizzly but there's is wired totally different then mine.

"Some issues" doesn't narrow things down much. Is this an electrical problem?


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[jdcool4]

Yes I bought the lathe used it never has been the way it was designed. I used to have to hold the first contactor for a few seconds of every use then it would work normal. Then one day I plugged it in and the plug was arching. I unplugged it waited a minute or two tried again no arching but the transformer wasn't making any noise so I ordered a transformer. Well I was waiting for the transformer I took out the first contactor and looked it over so I may have switched a wire I was pretty careful through. Also I am unsure of the new transformer don't put out the voltages that it shows on the out puts.

 

[Draw-Tech]

Hi jdcool4

Do you know if it is single phase or 3 Phase? Sounds like to me it may be 3 phase If you don't know, find a local motor re-builder in your area. I have found that most of the re-builders will have, or draw you a schematic, this is the best way to keep safe.
Good Luck

Jack
Draw-Tech

 

[jdcool4]

I think its single phase. But if i can find some one local that would help. Worst case is a drum switch

 

[Wizard69]

Yes I bought the lathe used it never has been the way it was designed. I used to have to hold the first contactor for a few seconds of every use then it would work normal.

Do you mean pushbuttons here? We have a small ENCO lathe at work that was purchased years ago that has had problems with the stop/forward/reverse pushbuttons. If this lathe is of that design then your best bet would be to modernize the controls.

Then one day I plugged it in and the plug was arching.

I would assume that if you are plugging the lathe in it is a single phase machine. Is that the case?

I unplugged it waited a minute or two tried again no arching but the transformer wasn't making any noise so I ordered a transformer. Well I was waiting for the transformer I took out the first contactor and looked it over so I may have switched a wire I was pretty careful through. Also I am unsure of the new transformer don't put out the voltages that it shows on the out puts.

It really sounds like you are lacking in electrical skills here. What you need is an electrician with industrial experience. For example I'm thinking you are confusing contactors with pushbuttons. Usually the word contactor is associated with a form of relay. As for swapping out hardware before its time, that can get to be real expensive fast. If you expect to do a lot of machine repair getting a good DMM ( Digital MultiMeter) is highly recommended if you are willing to learn how to use it. In the end there might be little wrong with that transformer.

In any event I'm suspecting that you have a case of bad controls here. A proper upgrade won't be cheap but I don't know the exact configuration of this machine.



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[jdcool4]

Its single phase. I know A lot about dc electrical not so much about ac. By contractor I am talking about the relay not the switch. I have three relays on this machine. If I knew what each contact on these relays did I could figure it out. the bottom 2 appear to be the control side the center appears to be the switched. But I have no clue what the top is.

 

[Smithers]

Can you take a photo so we can see what you are trying to describe.

Regards, Andrew

 

[Draw-Tech]

Hi jdcool14

Look at this Horbor freight uses almost the same parts as the enco machine, look over the pdf to see if it matches any of your parts. Electric at end of pdf.

Jack
Draw-Tech

View attachment Lathe.pdf

 

[jdcool4]

I have that same schematic in my manual. The high voltage circuit seems fine I can hold in km1 then km2 and the motor runs forward or km1 and km3 and the motor runs in reverse. At this point if I hold push to start the km1 relay activates but the fwd rev switch will make the relay disengage. If I hold push to start and inching the motor runs forward. But I have to hold both.

 

[Smithers]

Ok, lets get some basics tested, all with power off to your lathe.

1) Check the voltages on outputs of F! & F2 and record what they are.

2) Check continuity of K1, K2 & K3 de-energised (normal position) should be no circuit between inputs & outputs, energised (contactor pushed in) should be a circuit

3) Check resistance (ohms) of coil (what activates the contactor) on K!, K2 & K3 with coil wires disconnected (note what position they came from)

Let us know what you find.

Regards, Andrew

 

[Smithers]

Ooops, re my previous post...... power on to your lathe when checking voltages of F! & F2, must proof read my posts before I submit them

Regards, Andrew

 

[jdcool4]

I am getting about 7.5 to 8 ohms across a1 and a2 terminals on all 3 contactors. Fuse 1 I am getting 25 volts to both sides of the fuse. Fuse 2 I am only getting 3 volts to both sides. Ill try moveing it to a different spot on the transformer

 

[Smithers]

cool, that suggests all coils are on contators are ok.

3 volts dc is strange, but looking at wiring diagram this is only for led/bulb lights.

What about contactors, line in and line out open and closed?

Regards, Andrew

 

[jdcool4]

The old transformer had a 6 volt out for bulbs. The new one only has 24 and 110 but I am not getting anwhere near those some are way high and come down with load. I think the line in and out are ok because if I hold the contactor buttons the motor runs but I can check if it will help.

 

[jdcool4]

I got it running. The problem turned out to be a bulb in the power start button I was waiting till I got it running to replace. I blew it well playing with the new transformer and looking over the diagrams it is part of the coil circuit. I don't know how I missed it before. Now just to order a new power start button. Thanks for all the help

 

[StephenZ]

Hello, I hereby raise this thread from the dead!
I have the same lathe and have running issues that seem to be about the same as yours...my green light is on, though. My lathe turns on and the main relay/contactor pulls in, but when I engage the fwd or rev lever, the main relay/contactor pops out. If I push it back in the motor fires up fine...but I have to hold it in. I'm trying to follow the wires and current around their paths, but I'm not sure what voltage I'm supposed to see, and where. I get 28v or so coming out of the transformer and when I go to the back of the switch panel, it goes into the back of the green light where it's at about 18v. The other side of the light is about 6v and that goes on through the inching button and twist power knob. When I twist the power knob, the voltage on the other side of the light drops to 2.2v or so. That 2.2v +- goes through the inching knob, power knob, and back to main relay/contactor. Is the voltage supposed to drop like that? am I losing voltage at the light and not supplying enough for the relay? Doing my best to learn...thanks for any help.
Attempted picture to go along with it..

 

[Wizard69]

Hello, I hereby raise this thread from the dead!
I have the same lathe and have running issues that seem to be about the same as yours...my green light is on, though. My lathe turns on and the main relay/contactor pulls in, but when I engage the fwd or rev lever, the main relay/contactor pops out. If I push it back in the motor fires up fine...but I have to hold it in. I'm trying to follow the wires and current around their paths, but I'm not sure what voltage I'm supposed to see, and where. I get 28v or so coming out of the transformer and when I go to the back of the switch panel, it goes into the back of the green light where it's at about 18v. The other side of the light is about 6v and that goes on through the inching button and twist power knob. When I twist the power knob, the voltage on the other side of the light drops to 2.2v or so. That 2.2v +- goes through the inching knob, power knob, and back to main relay/contactor. Is the voltage supposed to drop like that? am I losing voltage at the light and not supplying enough for the relay? Doing my best to learn...thanks for any help.
Attempted picture to go along with it..
View attachment 104561

Do you have a wiring diagram for the lathe?

By the way what do you mean by the "relay/contactor pops out". If you are talking about an overload button on the contactor then there are a number of possibilities. One could be that the overload mechanism is malfunctioning. The second is that the motor is actually running in an overloaded condition. A third, if the contactor is adjustable, would be that it is set wrong. That is just the contactor there are other possibilities here.

One external possibility is that the contactor is simply dropping out, that is being turned off. This could be caused by a number of things from loose connections to the machine just sitting on a limit switch that actuates when you engage. By the way what do you mean by fed/rev here, is that spindle or Z saddle movement.

On some or the Chinese machines I've worked on, the electrical system and components can often be described as crap. I don't know the specifics of this machine so you may have perfectly fine hardware. IF not I'd seriously consider upgrading all of the machines electrical components. The Chinese seem to have issues with getting proper reliability out of simple stuff like pushbuttons.

 

[stevehuckss396]

If the plug was arching then it is probably the root of the problem not the contactor. Also use the drawing that was sent with the machine. If your machine does not match the book then someone likely changed something. To best repair the machine, restore the wiring to match the drawing in the book.

 

[StephenZ]

Do you have a wiring diagram for the lathe?

The wiring diagram is awful...it's only found online and is illegible...it's similar to grizzly, enco, etc...but just different enough.

By the way what do you mean by the "relay/contactor pops out". If you are talking about an overload button on the contactor then there are a number of possibilities. One could be that the overload mechanism is malfunctioning. The second is that the motor is actually running in an overloaded condition. A third, if the contactor is adjustable, would be that it is set wrong. That is just the contactor there are other possibilities here.

I meant the contactor goes from energized to de-energized when spindle switch is chosen. I don't believe the contactor is adjustable....

One external possibility is that the contactor is simply dropping out, that is being turned off. This could be caused by a number of things from loose connections to the machine just sitting on a limit switch that actuates when you engage. By the way what do you mean by fed/rev here, is that spindle or Z saddle movement.

Maybe that's the term, dropping out, when it de-energizes? Sorry, forward or reverse of the spindle, is what I meant. From the lever on the saddle that switches the rotational direction of the motor.

On some or the Chinese machines I've worked on, the electrical system and components can often be described as crap. I don't know the specifics of this machine so you may have perfectly fine hardware. IF not I'd seriously consider upgrading all of the machines electrical components. The Chinese seem to have issues with getting proper reliability out of simple stuff like pushbuttons.

LOL! I think that's the root issue here..crappy electronics. Nothing seems to have ever been changed or replaced, based on photos of other machines I've seen. Can I just change out the two contactors for spindle direction and the main relay/contactor, along with the thermal switch with new hardware that have the same specs? Here's the other question...can I just bypass all of it and use a drum switch? Or will that cause issues with the motor? It's single phase 220v dual capacitor 2hp.

Thank you for taking the time to help me out!
-Stephen
Oh, and while testing wires, I accidentally jumped the LED power light leads and blew it...yay. After that, the transformer only seems to be putting out 18v instead of the previous 28v. Goodtimes.