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Author Topic: Boxford 160TCL  (Read 38725 times)

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Re: Boxford 160TCL
« Reply #20 on: April 20, 2008, 04:33:40 AM »
Simon,

I think it is an over temperature cutout for the motor, hence it would be in the estop circuit. I just left it unconnected, as I was not going to overload the motor.

Ian

Offline SimonD

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Re: Boxford 160TCL
« Reply #21 on: April 20, 2008, 07:46:09 AM »
Ian,

Thanks for the info. I am trying to work out the motor reversing circuit needed but am not sure I understand the manual, it goes on about electrodynamic braking and tells you the size of the resistor needed but the circuit diagrams are unreadable to me.

If you have the time could you take a look at the attached pdf and let me know if you understand it? They don't seem to have bothered to label anything in the wiring diagrams and I haven't a clue as to what to do.

Thanks
Simon
Re: Boxford 160TCL
« Reply #22 on: April 20, 2008, 11:43:56 AM »
Simon,

Have you had the motor running? You will then get an idea of how long the motor takes to stop. The controller has no inbuilt braking system. Putting two high amp rated changeover relays between the driver board and the motor is the way to solve it, if either one is off, then a braking resistor is across the motor terminals and will give you the braking time. This value can then be used by Mach to delay a signal  (e.g. via a solid state relay) to the coils of the fwd/reverse relays. As I said, my TCL was fitted with twin changeover contactors with a mechanical interlock. The safest but complicated way is to measure the voltage on the braking resistor and when it is zero, it is then safe to change the motor diection. The wiring diagram is just as difficult for me to understand (I am a simple soul :)). It is lacking in details deliberately and as I understand it,  all those relays are just to do what I have just described. Anyone out there know any better?

Ian

Offline SimonD

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Re: Boxford 160TCL
« Reply #23 on: April 20, 2008, 01:15:45 PM »
Ian,

Yes, I have had the motor running and can vary the speed using a potentiometer wired into the speed controller.
When I feed the full 10v reference from the speed controller back into it, the motor it "hunts" as though it can't do full speed.
upto about 8v and it is ok and varies nicely with the input voltage.

The time taken to slow down is too long really so I would like to wire up some kind of braking. I am having trouble visualising the changeover relays you describe. I have attached a pic of the contactor which is present at the moment.

The contactor flips the direction nicely too so all I need to do is somehow get it to stop before I energise the contactor. There is a manual switch on the top of it and it reverses the direction ok but it is a bit violent!

Thanks
Simon
« Last Edit: April 20, 2008, 04:37:00 PM by SimonD »
Re: Boxford 160TCL
« Reply #24 on: April 20, 2008, 05:04:15 PM »
Hello Simon.

I have exactly the same machine, a Boxford 160 TCL with a 8-station-turret. I have a look at the Lenze-Spindle motor, its the same as yours. The two yellow wires are for the over temperature cutout, i don't use this two one. Look here:



I'll do the motor reversing with a switch for cw an ccw, first i try to do this with a relay for cw and ccw, but i can't get it to work. The switch is this one




Regards from Germany, Dietmar.

Offline SimonD

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Re: Boxford 160TCL
« Reply #25 on: April 21, 2008, 03:15:18 PM »
Dietmar,

Cool, thanks for the reply. Last night I got a copy of the wiring diagram of the 160TCL thanks to a kind gentleman who is retrofitting a 125TCL but for some reason has the 160 manual! The diagram indeed confirms that the two yellow wires are a thermal cutoff for the spindle. I may well wire it in as it is there but will leave it disconnected until everything else is working.

I will try controlling the spindle with relays first and report here how I get on. The wiring diagram shows how the relays on the existing board work so I will try and replicate those first. The guy I got the manual off had problems trying to control the spindle using a CNC4PC breakout board which doesn't inspire confidence but I have ordered it now so will try it when it arrives.

Typically, now that I have the wiring diagram it doesn't look that hard to wire in the original controller but as the Geckos have arrived, I may as well use them now!
Also, interestingly, the boxford 190VMC mill seems to use the same controller as it is shown in the manual as used for both and that is my next project after the lathe is finished!

Simon
Re: Boxford 160TCL
« Reply #26 on: April 21, 2008, 05:31:45 PM »
Simon,

Great that you got a diagram, it should solve most of your problems. I have not seen a relay like the one shown. Spindle speed problems, unless there is a fault on the drive card, can usually be cured by going through the setting up procedure in the manual. Normally it is the IR compensation trimpot that gives erratic running.
My 125 is a lot older than your 160, so I have to start from scratch with the motor control circuit.  I will send you a PM of the schematic. It would be interesting to see if I have got close to how Boxford did it.
If we cannot solve your spindle speed control here, Arturo Duncan at CNC4PC is very quick at replying to emails.

Ian



Offline SimonD

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Re: Boxford 160TCL
« Reply #27 on: April 21, 2008, 05:59:06 PM »
Ian,

Typically the wiring diagram is not the same as my machine! I spent this evening tracing the diagram to look at the relays only to look at the board and find that there aren't enough relays on it! It is very close, I must just have a different revision of the board.

The speed controller might have been "tweaked" by boxford to make the range 0-8v even though it ouputs a 10v reference. It would explain why it hunts when I put anything over 8v in it as it will be trying to overspeed (if that is a word!)

I think I have worked out the relay... It is a mechanically latched 4 pole switch. Energise A1-A2 and it switches one way, Energise B1-B2 and it switches the other way. It is used to cross over the speed controller output to change the direction. I just need to feed 24v into either the A1 or B1 terminals to get the direction change, hopefully this should be trivial with the CNC4PC board.
Does MACH3 turn the M3 & M4 output off again? I think I only need a 24v pulse to pull the changeover relay one way or the other.

Offline jimpinder

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Re: Boxford 160TCL
« Reply #28 on: April 22, 2008, 03:08:24 AM »
Just to go back a few posts - to the 5 wires to the motor - the two spare wires could well be for a large ballast resistor for the braking. I have one on my inverter (although three phase) - the principle will be the same. I understand it cuts the back e.m.f. and stops damage to the control electronics.
Not me driving the engine - I'm better looking.

Offline SimonD

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Re: Boxford 160TCL
« Reply #29 on: April 22, 2008, 03:20:35 PM »
Jim,

I first thought it might be something to do with braking as the original motor seemed to stop quite quickly and never really coasted as it does at the moment. However it appears to be temperature cut off for the motor and is confirmed on the wiring diagram as it is shown as connected to the e-stop/guard circuit which is where the wires went on my machine.

Thanks
Simon