10” x 30” lathe master electrical problem

6 amp should be fine since the relay does the hard work
M
 
Kungfo did you ever get your machine running?

You didn't specify, but I may have missed it, is the source feeding your lathe 120v or 240v-- the source coming into to your machine? I'd start out by eliminating two simple facets of the equation first. We are probably 98% certain it's not an incoming power issue...but put a meter on the incoming wires...verify as a process and move to the motor. Bypass all the other components and wire straight through a known 'good working switch' straight to the motor to ensure the motor is working. This will tell dispell any thought about one of the windings having popped or gone bad internally. The manner you desribed your machine's behavior and noise sounds to me like a capacitor or winding issue but then again it could be a contact on a relay that was spotting and intermittently receiving continuity.

However, we'd like to ensure the motor runs apart from all the other components first. Handle this leg of the equation and if we determine the motor is in good spirits we can move back to the control components and relays. It just sounds to me like it could be a motor or capacitor issue...that intermittency and noise you described. I'd eliminate the motor as being a possibility and then move from there.
 
Not, yet I am still trying to figure it out, source is 120v. It’s funny you suggest that because I was going head that direction. I have been studying this schematic I made and many others my question is “why is the relay/contactor needed?” Why couldn’t I just do away with it and some of the other safety measure and just wire direct to an on off switch?
 
You essentially had that with the toggle- no stop button or guard switch. But it's not as safe. The relay does the high current switching and overload protection and latching function so if you eliminate that you need heavier duty switches which cost.
Keep it stock is my recommendation- start button, stop button, guard switch, the whole banana
Mark
ps post 40 and 41 should have everything you need to get back on the air- let me know if you are still puzzled
 
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I agree with you, but let me run this idea past you first, since this has become basically a restoration project now. What if I used 2 relays like a 700-cf220 Allen Bradley, one for forward and one for reverse?
 
I'd still disconnect the main power coming into the machine and wire directly to the motor through a manual switch, you know to be in good working order, to test the motor and remove it from the equation as a potential host. That would squelch any concern regarding the 'jittering' behavior and remove both the motor and it's capacitors from the equation....if found to be in good working order. Considering the machine is wired at 120V, most likely your amperage is only going to be around 12-15 amps, depending on hp, so just ensure your switch that you use to test is rated for upwards of of 15-20 amps and you'll be fine. Bypassing this to test the motor isn't going to hurt anything.

And as others have stated, the relay is simply there so that you can have a safety margin built into the operation factor of the machine....namely the guard switch.

That said I believe your issue here is simply a broken neutral connection on the control circuit.

Once you've tested the motor-- I noticed in your latest schematic #36 that the past owner or someone has the control portion of the relay (A1 and A2) not wired conventionally. A1 is usually always the terminal for your hot and A2 is for your nuetral connection in a single phase situation. Someone has that wired backwards here and is using A1 as the nuetral connection and A2 for the hot. Considering this case, that loose wire coming from your guard switch would have to go to A1 at your relay in order to complete the control circuit. Namely, the neutral side of the circuit. At this point, there is no neutral connectivity there at the A1 terminal, in order to complete the neutral circuit.
 
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I think you are right on all accounts, I have not had to test it this week so far I am hopefully going to get to it tomorrow or this weekend
 
I just got back from an electrical supply house and the guy there said the same thing about the neutral on the guard switch, he thought that loose wire needs to go to twelve, A1 and A2 I wrote those backwards on the diagram you are right on those also. Thanks for all your help, I will test the motor by itself and report back what I find.
 
Ok, you're saying you just wrote in 'A1' and 'A2' backwards, correct? And yes, it does appear that landing that wire on #12 would indeed complete that neutral portion of the circuit. (( #12 on -Position 2- switch that is (schematic drawing #36)).

Keep us posted. This is a very simple repair, sometimes the forest of wires prevent one from seeing the tree. Processes of elimination is the best course of action. Don't worry we'll get it and have that machine up and running again.
 
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