Gear drive Chinese Mill 3 phase

I'm back, I eliminated the problem of the 3rd leg. That didn't solve the issue, I checked the transformer and I am not getting any power out of it with the machine turned on.
 
Check that the transformer is getting 230VAC on the input with a volt meter, if it is, then check the output. Typically the there is also some fusing wither to the transformer, or/and on the output. Check the fuse to see if has continuity (not blown).
 
Do you have a photo of your panel enclosure? How about a factory schematic? Even if it is printed on fortune cookie paper it might help a lot.

You should be able to poke around with a meter to see what's happening- power in, power out, power distro. I'm not convinced your floating leg is isolated to the motor only. I worked through the same fault description myself a few months ago with my Nardini, in my case it was the phasing. Either way, it is constructive to prove out the panel wiring.
 
Ok, I have it running now, I found that The previous owner had wire nutted the wires together on the transformer without removing the ferrules, I believe they were in a DIN rail before, I clipped the ferruled ends off and wire nutted them back together, Then tried re-orienting the main wires coming in from the converter again, I got it to work now, However it will sometimes make the static converter start buzzing, When that happens, If I push the KM-1 contactor in manually it stops doing it then works fine. I am puzzled by this, But that doesn't take much, I am learning this stuff as I go with help from you guys!

I got the mill as a non working machine, But When I felt the main disconnect switch, It felt bad, It was real crunchy. So when I wired it up before replacing that switch, I would get nothing, After replacing the main power disconnect switch, The static converter would make the click when I turned on the breaker, So the original switch was bad. I am wondering now if that contactor is sticking making the converter buzz? If none of this makes sense to you, Don't be surprised, When it comes to this stuff, I don't know my Crapper from a hole in the ground, But I am learning.

Edit to add: There are no fuses on this machine, I checked that first, Because when I was having problems with the Enco lathe a couple months back, I had blown both of the old glass fuses.
 

Attachments

  • DSCN4434.JPG
    DSCN4434.JPG
    362.1 KB · Views: 9
  • DSCN4433.JPG
    DSCN4433.JPG
    362.3 KB · Views: 9
Last edited:
So what I am trying to say is, I still have an issue, The mill will work and then the next time I turn the breaker on, The static con, Will just buzz until I press the contactor in. Then it might not do it next time. The weird part is, That contactor is for the forward direction of the spindle motor.
 
Can you test for voltage on the coil wires of the contactor? I'm wondering if you have full control volts. Contactors and relays have a threshold voltage (usually its rated voltage) where they will drop out if they fall below. Same reason the wild leg is problematic, any loss of voltage due to dirty grounding, weak connections, etc. will cause dropout.

The other thing I would do if it's not passing current when the contactor is closed is clean the graphite or copper contact points on the contactor. Trying to isolate where the fault is, on the 40v circuit, or the 240 side. Contactor deals with both. Got multimeter?
 
What I don't understand is, With the main power disconnect switch off, The static con will still hum until I push in the contactor.

So Basically, Once I push in KM-1 contactor, Then the spindle motor will start turning, Then I can shut it off with the stop button and then restart it with the start button, Prior to that, Nothing works including the power light until I push in KM-1, After it is pushed in, Everything works. Also the power head for the up and down will only work when the spindle is running.

I have a fluke multi-meter, I am learning how to use it.

So what you are saying is, The transformer may not be supplying enough voltage? It is 208 or 240 input,24 volts output. According to the label it is wired correctly, The red wire is connected for 208, And the orange wire for 240 is isolated (wire nutted off) The white wire is grounded.

I am beginning to wonder if this machine just doesn't like Static phase converters, There is a lot of stuff hooked up to it. The DRO, doesn't work either, It's 110 volt.
 
I wish I knew how to put a video on here.

Also, I do not have a manual or a diagram, I know what the 2 left contactors are for, But I don't know what the others are for, If it is like the Enco was, one of them should pull in and supply everything with power, None of these do that? And when I press them in, THe only 2 that do anything are the KM-1 and KM-2 which are for the spindle motor.
 
Last edited:
If you read 38v instead of 40v, then yes, you will have hell getting the contactor to latch.

I don't have any experience with static converters. The only time I get a buzz out of my rotary is if I'm feeding the wrong leg, but that probably doesn't help you. I don't know their fault behavior.

You know your machine works fine when the contactor is latched, so the fault to pursue is going to start at the latch coil. Unfortunately, this step will require measuring the voltage, because that will tell you if the contactor is getting what it needs. If yes, check the connections to the contactor. If no, look for shorts or weak connections. By following the logic, you can find it and fix it.

Edit: Voltage drop (like losing 2v off the contactor from the transformer) is caused by loads (resistance) in the circuit. A good transformer with a damaged wire may show reduced voltage on the output leg.
 
You must log in or register to reply here.
Back
Top