PDA

View Full Version : Align power feed problem help please?



bollie7
08-23-2017, 07:22 PM
Gday
I have an align AL235 power feed unit on my mill.
History first- the mill has not been used since early 2009 until recently, when I fitted a VFD and new motor to it.
When last used in 2009 the feed unit was working however now its got a small problem.
The motor only runs in one direction. At first even that was not too good so last night I opened it up to have a look. It was immediately obvious that previous users/owners had had it apart. As it turned out one of the screws holding the top bearing for the motor was loose. As soon as I tightened that up the motor spun freely.
It still only runs in one direction. The pot works fine.
The two micro switches that are activated by the direction handle are working correctly.
So I'm wondering of there is a problem on the board itself.
Does anyone have any experience with this sort of issue with these units?

Thanks in advance
Peter

Erich
08-23-2017, 07:47 PM
Is this using a separate power cord or is it getting juice from the vfd?

bollie7
08-23-2017, 08:02 PM
Separate 110V supply from transformer. (we have 240V ac here in Australia) No connection between VFD and transformer.

peter

Mr Fixit
08-23-2017, 09:45 PM
I have to preface these comments with do any of this ONLY if you are comfortable and now your way around electricity.

When you say the micro switches are working correctly do you have a electrical meter to check and see if the power is at the micro switch and going through the micro switch? It could be the switch is out of adjustment but moves to the eye.
You could also switch the wires from the one side of the motor that works with the side that should work on the good micro switch and see if it runs the other way only. This would tell you the micro switch is in question and the motor is OK.

Above ALL be careful with live equipment and your self. Good Luck and keep us informed if possible as to the outcome.

TX
Mr fixit for the family
Chris :)

bollie7
08-24-2017, 06:06 AM
I had another go at the feed motor after work this afternoon. Turns out my problem is whats called an ID10T user error. DUH :(
When I got the mill, the travel limit switch assembly was missing. All that I go t were the two adjustable stops that go on the front of the table and a micro switch attached to the feed unit. I would have sworn that the feed unit was working in both directions back in 2009 but I can see now that that could not have been the case. The feed motor does indeed run in both directions depending on if the micro switch is pressed in or not.
I didnt think to try that yesterday as I thought it was just a limit switch that stopped the motor when pressed in.
So can someone post a pic of a complete limit/travel stop (the bit that holds the switch) please? So I can get an idea of what it looks like.
Thanks once more
Peter

Cuttings
08-24-2017, 11:24 AM
Here is a picture of the limit switch assembly on my mill. The align power feed is relatively new. Hope this is what you are looking for.

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=1229&d=1495078724

bollie7
08-24-2017, 05:52 PM
Thanks for the picture Larry. One more question. The square bit that sticks out either side near the top and obviously trips the switch when it hits the stops. Is that spring loaded to return to the centre position once the table moves away from the stop?
Thanks
Peter

Cuttings
08-24-2017, 06:33 PM
They are individually spring loaded so I am assuming there are two switches in there. Once one opens the circuit it won't move in that direction any more. I just looked up my manual and it has a circuit diagram and it shows 2 sets of double contact switches. One set to change the direction and the other to limit the travel. Mine is an AL-500D horizontal model but the circuits are probably the same. If you want to try and get the travel stop assembly the part number in my manual in P01943. If you don't have a circuit diagram I would scan it and sent you a copy. Now that I look at the parts blow up I see the two plungers in the limit assembly have a common spring between them and there is two micro switches in the housing.

Paul Alciatore
08-24-2017, 08:34 PM
The motor only runs in one direction. The first thing that I would do is put a VOM on the motor terminals and see if it is getting Voltage for both directions. It is reversible so it is probably a DC motor but you can start with an AC scale on the meter and a higher Voltage range, like 500 VAC. If it is definitely a DC motor, switch to a DC scale. You have already opened it up so taking some quick readings should be easy. Do be careful and don't get a shock.

Once you know if the motor is getting a drive Voltage or not, you can either look for a mechanical problem that prevents it from rotation or for an electrical problem.

As for that limit switch, it could easily be the problem. It is in an exposed position where coolant can easily get in it. A switch in there could easily be stuck in the closed position. A quick squirt with some alcohol followed by exercising it could free it. (Exercising it means pushing it in and out several times, perhaps with additional squirts of the alcohol.) Giving it a good washing can't hurt. And yes, you can do this with power on: with alcohol, not water.

JCHannum
08-24-2017, 08:47 PM
The control box must have two limit switches, one for each direction of travel. Travel is selected with lever on the drive unit and continues until interrupted by limit switch. Moving the control lever will reverse the motor allowing it to move off the stop position. If there were only one switch, the unit could not be reversed.

It took me a bit to sort that out with my first installation.

bollie7
08-24-2017, 09:44 PM
All I have is one micro switch which I'm beginning to suspect is not original. When the switch is not activated the motor runs in one direction but not the other. When the switch is activated the motor direction is reversed (with the handle reversed as well of course). The problem with this setup is as soon as the table moves back away from the switch the switch opens again and the motor stops. I have a heap of micro switches so I'll re wire it for two which should solve the issues.
peter

Paul Alciatore
08-25-2017, 01:06 AM
My Grizzly mill has the same limit switch assembly. I guess they don't waste a good design. I opened it and took some photos of the inside. Yes, the two plungers have a common spring. And yes they also operate separate switches, one for the left limit and one for the right. Here is a photo:

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=1728&d=1503637064

There are two switches and they are stacked one on top of the other so it could look like just one. Here is another view:

http://bbs.homeshopmachinist.net/attachment.php?attachmentid=1727&d=1503637063

As best as I can tell, the cable has three wires: black, white, and green. The green definitely goes to the Right Limit switch which is the upper one in the photo and the rearmost one when it is mounted on the mill. The white wire goes to the Left Limit switch which is the lower one in the photo and the frontmost one when it is mounted on the mill. The black wire seems to be a common and I believe it goes to both switches via a yellow jumper wire that is also visible in the photos.

If those Chinese switches are close copies of the Micro line, then the green and white wires are going to the Common terminals on the respective switches and the black/yellow common connection is going to the NC or normally closed terminals of both of them.

There is no guarantee that the wire colors will be the same, but I hope this helps in rewiring yours.

bollie7
08-25-2017, 07:40 AM
Thanks for going to that effort Paul.
I really appreciate it.
I found a couple of micro switches in the shed this afternoon and wired them up. Bingo, all is good now. I'll probablymount them in a box similar to the factory one. (I already have the box) Here in Australia a replacement limit switch assembly is $88 plus post, so close enough to $100. Even buying from the USA the price is around $55 aus plus freight. So as I already have most of the bits I think I'll just potter around and make my own.

regards
peter

Paul Alciatore
08-25-2017, 10:00 PM
Great to hear you have it working. If you don't have the original box, that sounds like a good excuse to buy a 3D printer.

BTW, I was really surprised at how clean the inside of mine was. I would have expected more to have gotten into it. I did not clean out anything before taking those photos.

bollie7
08-26-2017, 05:49 AM
Speaking of 3d printers, my feed unit was also missing the bottom gear cover, so having access to a small 3d printer, I got a friend to draw it up in inventor and save as a .STL file. Then I printed a new cover. Worked out quite well.
If anyone wants a copy of the stl file for the cover I'm happy to forward it on.

peter