Enco 12 x 36 Model 510-2584 Power Start Issues

[Lindy]

Good Morning,

My Enco 12 x 36 Model 510-2584 (110V single phase) is having some issues and I'm not real sure what to do. Here is some background

1. It would not go in reverse, I took the switch apart, one of the indents was broken and the broken piece and spring (it has 4) was preventing it from physically rotating, I removed the broken piece and reassembled. I made a diagram of the wiring before I took it apart and about 95% sure it went back together the same way. It now will for in the forward and reverse rotation.

2. The power start switch has been broken for about a month, the knob fell off of it, It is just a 4 post switch (2 wires for the Power Start, 2 wires for the indicator light) I had just been physically jumping across the two power start post (I know its not the right thing, but it allowed me to use it until I got a replacement).

Now that I've taken the forward/reverse switch apart, the Power Start will no longer energize the contactor, you have to manually push the little square button on the contactor. Once that is done, everything works fine, it goes into forward/reverse, Emergency Stop works, Inching Works, and Power Light illuminates.

Does the forward/reverse switch circuit into the Power Start switch? How does the Power Start energize the contactor? (by that I mean, does it do it by completing a electrical circuit, or a ground circuit?) Other than checking for resistance to see if there are breaks in wires, how would I test the Power Start circuit? if there is actual power that runs through it when the circuit is completed, how do I test for it and what kind of voltage am I looking for? One of the poles on the Emergency Stop switch, the wire (a red wire) is split and also runs into the Power Feed, Im assuming this is the power feed since its common? When testing for voltage on a system like this, how do you do that? Do you put a positive lead from your multi meter on the wire, and the black on a grounded piece of the lathe? I apologize, my electrical knowledge is very very basic, I can normally manage to work my way through things, just need some help with understanding some of the basics.

v/r

Thomas

 

[markba633csi]

Need some info on your machine- we have a manual for a similar model in our downloads section;
If you join as a member you can access the file. I can look at the file and tell you if it has a schematic diagram and if it matches.
But we need to know the layout of your control box:
A) Is this a two or three contactor model? Some early models have a pair of contactors and a small 3rd relay
B) Does it have a transformer? What is motor HP? Running on 110 volts pulls high current and burns up contactors fast
C) Do you have an apron lever actuated forward/reverse? The switches for that often fail since they get a lot of use

 

[Lindy]

I can take actual pictures when I get home tonight, Im not sure how to join as a member, maybe has to do with post count. I have a Operators Manual for it, I can take pictures of what ever is needed, just hard to do during the work day since, cell signal in this building is non-existent.

A) It is a 3 contactor model K1, K2 and K3 (3TB41)

B) It has a Transformer (BKC-50 primary 0-110v-220v secondary 0-6v, 0-29v)

C) It has a apron lever actuated forward/reverse

 

[markba633csi]

OK, understood. The manual we have doesn't match it, but I have a diagram that might. BTW donations are always welcome
Testing for voltages is done by putting one probe on the 0v point of the transformer and probing around the circuit with the other probe.
Having clip leads for your meter makes it much easier.

The power latching circuit for the 1st contactor is what usually fails, either from a broken switch, broken contactor or loose wire.
Apron lever switches: what type do you have? early models have a single barrel-shaped switch, later models have twin microswitches
The barrel one can be purchased on Ebay- it's a special type

Below is a typical 3 contactor diagram: Ignore the diagonal mm lines; it just indicates what wire gauge was used
This shows the barrel apron switch SA

 

[markba633csi]

Here is a more detailed diagram for the control section: (barrel apron sw)
The leftmost contact on the forward/reverse apron switch enables the start sequence. If it's broken the contactor KM1 can't pull, but it can be latched manually by pushing the test button on top of KM1
It sounds like your issue. The leftmost stop pole of the switch SA should be closed with apron lever at center

 

[Lindy]

Ok, sorry I'm slow, yes I will most definitely register as a member

When you say the 0V on the transformer, what exactly are you referencing?

My machine uses a twin microswitch apron lever switch.

So I guess my main concentration is going to be on the power start switch, circuit. You can physically push the black square button on the KM1 contactor, and it will stay latched until you unplug the machine from the electrical outlet. But it wont latch by using the power start.

And I apologize, I don't understand the wiring schematics very well, I don't know what the symbols mean or the numbers.

 

[markba633csi]

Look at the diagram in post #5 above: On the transformer symbol you can see the outputs 0, 6v, 24v and 29v
0 is the one I'm referring to. It's the common point for the contactor coils and lamp loads.
Since you have jumpered the power start switch, that leaves the microswitches. One must be bad. If you have a multimeter
you can remove and test them for continuity one at a time.
Be sure to label the wires or take pictures of how they connect. Also is it possible the actuating cam has come loose from the control shaft?
Check that first. As you operate the apron lever (with power off) you should hear the switches clicking.

I'll see if I have a more accurate diagram that shows the microswitch hookup- it's a bit different than the barrel switch
The machine needs to have the apron lever in the center position before the KM1 contactor can latch. That requires the microswitches be working properly- one of them must be faulty or disconnected
How many wires going to the microswitches from the control box? There are a couple variations

 

[Lindy]

OK its starting to make a little sense, I will test at the three circled points for continuity, what do the numbers mean on the schematic? for instance at the Power Start, it has a 14 and a 13, then right below it a 5 and 4? I'm going to suspect how its acting and how I'm starting to understand that its going to indeed be the micro switch, and it really didn't occur to me until now, it wont power start unless its in neutral, and it doesn't know its in neutral unless it has continuity through the switch. It doesn't look like micro switch are available anymore, guess Ill need to buy a barrel valve.

There are 4 wires that go to the micro switch, a red one that is split so it feeds 3 poles, then 3 wires on the opposite side cant remember their colors right off.

 

[markba633csi]

Don't despair, microswitches are freely available at most electronics suppliers like digi-key and Mouser. Microswitches are preferred over the barrel switch and more reliable, but even they can wear out after long service. Lathes usually use an industry standard microswitch type.

Don't worry too much about the numbering at the moment since that diagram doesn't represent the microswitch version. Yes you need continuity thru BOTH microswitches before KM1 will latch. You'll likely find that pin 5 of the overload relay is not getting power, thus KM1 isn't.

It might be best/easiest to just remove the microswitches and test them separately- but just be sure you know how to reconnect them.
Make a drawing or a sketch. Each of the 3 switch terminals will be marked. The terminals are called Com, NO and NC. Keep track of that;
very important. When you get the switches out I'll show you how to test. You have a meter yes?

 

[Lindy]

Yes sir I have a meter, I will get it out this morning