miller

Hi guys, I have a chinese milling machine which is exactly the same as the Clarke CMD300 model from what I can tell from photos. It stopped working a while ago and I was told the power transistors were probably the cause. A club member took the control panel away with a view to fixing it. However, after replacing the transistors and connecting the panel to his machine he found there was still a fault somewhere that he can't pinpoint. A new panel is about £90 so I was wondering (not knowing anything about electronics) if the control panel I saw on e-bay might do the job. The main spec of my machine, taken off the motor plate is : 350w motor, DC 230v, 2.2A, class e (reversible)

The spec of the other controller is : Input AC180v-AC260c 50/60Hz, output current 4A, adapter power 50w~500w(110v output 300w, 220v output 500w) Fit motor voltage: 220v, Armature output volts DC0~90v/110v/220v, Excitation output volts DC100v-1A/DC200v-1A.

To my untrained eye it doesn't seem too far away, but would it do the job? If anyone out there could help with this I would be very grateful as it's over 12months since it stopped working!

Regards

Ron

That sounds about right. Can you give a link to the new controller to check, it sound like it may be a KB Electronics one. I don't think you'll need the excitation output as the cmd / x1 mill has a permanent magnet motor IIRC.

Hi, I don't know how to post a link. What I don't understand is it says the item is located in Dunfermline but the business is in China!

Ron

Hi Ron,
You could just give the Ebay item number. To post link first copy the URL from the URL box in your browser. (To do this highlight the URL then press control C (Or right click and select copy.)) Then in your message on the forum highlight the text in your message that you want to take you to the link. In the lower row of buttons at the top of the message box select the sixth one from the left (Blue disk with a chain link at the bottom.) This will bring up a box to enter the URL. Past the URL that you have copied by pressing Control V or right click and select paste. These instructions are for windows. I think they will also work with Linux but I have no idea how you would do it if you are using OS X.

Les.

I have found it, item no. 181473818094. Actually I have a very similar one but lower voltage, which it haven't tried yet. It should do the job fine, I just have a slight worry about whether you can leave the field supply ("excitation" ) open circuit without damaging the unit. One way to avoid that would be to just connect it to a resistor to draw about 0.1 A, which on the higher voltage range would be 2000 ohms, but it would have to dissipate 20 watts which is quite a big resistor! Or ask the seller if the excitation output can be left open circuit.

Edited By John Haine on 28/09/2014 09:36:42

Edited By John Haine on 28/09/2014 09:37:07

Hi John,
Your link to item number 181473818094 did not work. This link should work.

Les.

Hi John, thanks for reply. I have contacted the seller to ask about the excitation query so will wait and see if I get a reply. I wondered if excitation was there just for a particular motor that needed it, ( I assume it's like a kick start) . As I said before I don't really understand electronics!

Ron

Ron,

I've already used one of these controllers and can confirm that the field excitation can be left alone....Basically it is just a raw dc supply generated by rectifying the mains input fed to it....

I'd be surprised if the seller can answer a techie question....

The speed control aspect of it is done using mosfets al a Sieg unit which we all know to be a bit unreliable, thats not to say that these units suffer from reliability issues....

Hi, after all your help I have ordered one of them, at that price I've not much to loose as my machine is sitting idle anyway. Will let you know how it all works out later!

Thanks everyone.

Ron

Ron, let me know how it works, may help with my own! As you say at that price... The excitation is needed if you have a wound field motor, but your mill has a permanent magnet.

John, thanks for that info, actually I have found that some of these Chinese sellers can help.

Les, I didn't insert it as a link! The site software did that....

Will keep you posted John.

Ron

Hi guys, I apologise for the delay but the thing only arrived today due apparently to a smudged delivery address. I will try it when I get a minute or two. A question for John Rudd! All the terminals are marked +/- except power ones, so are these the same way round as the others John? I don't want to blow anything at this late stage! I also take it the earth will go to the screw near the end of the terminal block. As I said earlier I'm not too well up with electrics/electronics.

Ron

Ron,

Connect as follows:

With terminal strip facing you, terminals are numbered 1-10 from left to right.

1+2 goes to a switch with a Normally Open contact, close the switch to energise the controller.

The existing switch on the potentiometer, if it is the original one, is no good. The contacts open when the pit is advanced, this was a safety feature on the existing board.

I suggest obtaining a switched pot from Maplins of the correct value to replace the pot supplied with controller(5K?).

Next connect the new pot to the controller, terminals 3+4, connect the middle tag of the pot to 4 and one of the outer tags to 3: if the speed is the wrong way round, use the opposite, unused tag...if you look at the pot with the spindle pointing at you, you need the left hand tag to go to 3.

Terminals 5&6 go to the motor, 5 is Positive.

7&8 are not used, they are to excite a wound field winding.

9&10 is the AC input connect Live and Neutral from your incoming supply via the NVR switch

Finally: Do Not Omit the Earth connection. This is the screw holding down the case at the left hand end of the terminal strip.

I hope I've covered everything for you, if you need more help please email me as I'm not participating.(except in this case)

Edited By John Rudd on 17/10/2014 13:55:04

Thanks very much for that John. Not quite sure what NVR switch is but will follow wiring from mains in through to the original board.

Ron

Hi, sorry for the delay in getting back, but have wired the new controller in today and hey it works a treat! Been waiting ages for a friend to repair the old one but don't need it now hopefully. Thank you all for your various inputs and best regards.

Ron