Lathe Jaguar VXS inverter - remote pendant

[raynerd]

Hoping for some info guys. I'm using a Jaguar VXS inverter to run my lathe motor and the pendant isn't right. The variable speed pot does not change the speed in a linear fashion, from stopped to full speed in a touch, incredibly sensitive to get it to the right speed and then when set at a speed, the speed can often creep up.

Has anyone experience with this inverter and can describe the best way to make a new remote pendant and also suitable settings for the inverter. On my old pc many years back I had manual but I struggled to make head nor tail of it. I need to fully rebuild the pendant as it clearly is t correct either.

Any help appreciated. Photo attached.

[angus]

i have some jag/imo manuals at work.... will see if i have one for that.....

[David Jupp]

Assuming you have the correct value and type of potentiometer as per the manual (LOG or LIN), I wonder if the problem could be a dodgy connection on one of the 3 wires from the pot to inverter.

For a speed control pot, control mode should be set to voltage - if the inverter has a current control mode (many have both) this is not for use with a pot.

[EDIT - also just thought, an open circuit at one end of the pot track might give similar problems - not sure how likely such damage is though.]

[David Jupp]

Manual available at http://www.as-uk.co.uk/downloads/manuals/imo_jag_vxs.pdf

Speed control via pot looks fairly standard - though I note it doesn't suggest type of Pot (LOG/LIN).  Since it's a voltage input, the exact value of the pot should not be too critical - a higher value ought to be safe (will draw less current).

[mfletch]

I've made my own its not hard here is some instructions if they load

[raynerd]

Well it was February when I posted this and I've still not fixed it! This is the week!!!

mfletch - I can't see a circuit diagram just the wiring and settings (which are useful)

David, mentioned that the pot is not identified as log/Lin - Does anyone have  any suggestions as to what  I buy from maplin tomorrow - size and log/lin?

I am really still stuck as to an appropriate circuit and would really appreciate any guidance as I have a use for my lathe after any months of inactivity. I finally have a week off work and free...

[AdeV]

Assuming the lathe starts at a decent slow speed, and assuming top speed is OK; use your multimeter to read the maximum value of the existing pot (read the outer two terminals), that'll give you the value you need.

To determine if it's log or lin, take 2 readings at 1/3rd and 2/3rds travel. If the line from zero to maximum through those two points is more or less straight, it's linear.

[raynerd]

Ade, thanks for the info, good to speak to you again, not been on in a while.

The current controller is in bits. It didn't have a slow speed at the end, just started at full speed (which was very high!). The only way to get a slow speed was to set jog, which gave about 40-60 rpm. Without jog, it was just full speed.

As I have said, it has never been right and the control of the speed has never been linear. Would it be too much of a presumption to suggest that the old/existing pot is the wrong type and try the opposite.

The original wiring of the controller/pendant was also off in that the start button didn't work correctly with the jog. If you stopped the machine, put it to jog, it would jog. If you then stopped it and flipped off jog, it would start without hitting start! The whole thing never worked properly hence why I'm keen to try a new circuit.

[John Rudd]

if its a logarithmic pot the value should have an A or a after it, if its linear then a B or b

[mfletch]

on my jaguar vxr I think it is I used a 10k pot

[raynerd]

Cheers guys . Mfletch - do you know if it was log or Lin and do you or anyone here have any idea of an appropriate circuit?

[raynerd]

Just looked as I've only just got home, the current pot is an alpha 7L4 a so I'm guessing that is logarithmic.

[PekkaNF]

Not sure if this helps, because you asked help of Jaguar VFD and I haven't used them. Others yesh.

I use 2,5K to 10K LINEAR potentiometer. I don't think that exact value is critical, as soon as it does not sap more current that VFD provides and it is not too huge, because miniscule current is also a problem on control circuits.

Your symptoms sounds like: potetentiometer is of way too low or high value (like under 1K or over 100k), or logarithm (very different behaviour, broken, connected wrong (+ or GND on wiper, or one pin disconnected).

Maybe potentiometer cable is  nonshielded, shield connected to wrong pin or not connected all.

Or at very worst potetiometer supply failed, but usually the whole unit would be pretty nonresponsive then.

http://www.electronics.dit.ie/staff/tscarff/DT089_Physical_Computing_1/LABS/LAB_3/pot%20wiring.jpg


I would check:
* Wiring per manual. You want one leg to show positive voltage, typically 12, 10 or 5 volts DC and other end grounded. The wiper must go to analog input.
http://www.electronics.dit.ie/staff/tscarff/DT089_Physical_Computing_1/LABS/LAB_3/pot%20wiring.jpg

Multiturn or servopotetiometers can have different pins that you think:
https://www.bourns.com/pdfs/3547.pdf


* Disconnect potentiometer wiresat VFD terminal from the pendant and connect NEW potentiometer on VFD pins with short wire, power it up and measure that voltage between GND and wiper pin varies smoothly when you move pot from one end to another one.

If this works, then I would check the pendant and it's potentiometer.

Pekka

[John Rudd]

Chris,
I've mailed you a drawing....,the forum doesnt support photos from my ipad anymore...

[raynerd]

Evening

John has kindly provided a circuit diagram and lots of support in creating a pendant. I now have the parts on order so they should arrive by weekend. I have removed the old pendant that has never correctly worked and I have gone through to check the parameters that I don't believe I ever correctly set up either!! I can't get the bloody thing to run at all at present despite F01 and f02 set to zero for keypad mode, anyway, my little boy woke up and started crying so I've had to pack it in for the night, I'm sure I'll figure it out tomorrow. (edit - reading the manual and I need to make a terminal connection between p24 (24v) and Forward/Rev to give it a RUN signal)

I made a note of the functions I don't truly understand what they should be set to... if you have any suggestions as to even a sensible start value, I would appreciate it. I've also linked to a picture of the motor plate if this is needed:

F03 - Maximum output frequency (currently set to 150)
F04 - Base Frequency
F06/07 - acceleration and de acceleration time (0-3600)
F10 - motor poles (set to 4 when I got it, but can I tell my motor is definitely 4 pole?)
F12 - PMW carrier frequency

Really appreciate any advice as to sensible starting values...

Motor plate : http://raynerd.co.uk/wp-content/upLoads/boxford26.jpg

Chris

[Sea.dog]

F03 - this is the maximum output frequency which, for an AC motor, is proportional to the RPM, so for 150 (Hz) you'd be getting three times the RPM. I use a top frequency of 100Hz.
F04 - is the minimum output frequency i.e. it controls the lowest RPM you wish to use. F03/04 of course are the maximum and minimum limits of the potentiometer.
F06/07 - are the ramp up and ramp down times. They control acceleration up to running speed (as determined by the output frequency) and deceleration (controlled by injecting a DC voltage to brake the motor. I use 2.5 secs. for my AUD
F10 - That depends on the motor. If you can't find a reference on the web then you'll need to open it up to determine the number.
F12 - Carrier frequency is the operating frequency of the internal digital circuitry. My TEAC was set to 4kHz and gave an annoying whistle. I set it above audible range. This can cause RFI (interference) problems depending on where the VFD is sited in relation to other equipment or radio/tv receivers.

Graham

[Pete.]

Motor poles you can tell by the speed rating on the motor plate if it has one or just by measuring the rpm at 50hz. If your motor is doing 1400-ish RPM at 50hz it's a 4 pole. If it's doing 2800-ish it's a 2-pole.

[raynerd]

Cheers Pete, will give that a bash today.

SeaDog I really appreciate your time in posting all that and I think I'm good with setting all except f3/4, I still don't feel I truly "get it"!

F03 - this is the maximum output frequency which, for an AC motor, is proportional to the RPM, so for 150 (Hz) you'd be getting three times the RPM. I use a top frequency of 100Hz.
F04 - is the minimum output frequency i.e. it controls the lowest RPM you wish to use. F03/04 of course are the maximum and minimum limits of the potentiometer.[\quote]

So are you saying that that freq is 3x RPM. So if you are running 100hz you only have a top speed of 300RPM? I am missing something - I'm sure it is me being stupid just I am still none the wiser as to what to set theses values to!

[hopefuldave]

Not too sure on F04 - on my own ABB and others I've set up the "base frequency" is the normal mains frequency the motor expects, i.e. 50Hz for rest of the world, 60Hz for America.
 The VFD uses this to work out the V/Hz curve when driving the motor, below base frequency the motor voltage is lowered as the inductance of the motor means its impedance drops with frequency, setting base frequency too low will apply too much voltage and send the motor over-current. Having the right V/Hz curve below base frequency puts the motor into constant-torque mode (one reason why you still need back-gear and gears to get best performance from a VFD-motor combination) and once above the base frequency the full mains voltage is applied, giving close to constant-power operation.

There should be a separate parameter to set the minimum frequency (F02?), which could be 0Hz if you wanted, be aware that motor cooling will be reduced a lot as the motor and its fan slow down (I *think* airflow is proportional to the square of the speed?) so either a thermal switch to halt the motor if it overheats or a cooling fan at low speeds is a Very Good Idea (I fitted a big axial fan on the end of the motor that "fails safe", comes on with the VFD's mains power and cuts out above 35Hz from the VFD** when the motor's own fan should supply enough cooling air, I run the motor down as low as 10Hz for jogging, a bit notchy but useful now and then, set my maximum to 85Hz to get 2500 RPM from a 1500 RPM lathe *for short periods* 150Hz may be a bit much unless the motor's built for it, a 3000 RPM motor would be running at 9000, might do a good impression of a hand-grenade).

HTH,
Dave H. (the other one)

**you may have the option to configure one of the VFD's relay outputs to open at a configured "supervisory frequency" if you want this feature and the VFD supports it

[Pete.]

I actually typed the same thing this morning about base frequency but deleted it because I didn't know if it was the terminology they used for minimum.

[hopefuldave]

Looking in the linked manual, the Jaguar uses F36 and 37 as high and low frequency limits under speed control by panel or potentiometer etc., F30 as "start frequency", F03 as an absolute limit to prevent motor overspeed. I suspect "start frequency" is independent of the low limit but I could be wrong - I expect it may ramp from the start frequency to the low limit at start-up, then operate between that and max frequency - this may be worth experimenting with

HTH
Dave H. (the other one)

[appletree]

Not wishing to hijack this thread, but my question is pertinent. I have a Mitsubishi inverter for which I have built a pendant, I have been able to configure the inverter so it responds to momentary push button inputs, so providing true no-volt fail safe.

I also have the same Jaguar inverter and would like to know if and how the above functionality can be programmed  Cheers

[John Rudd]

Appletree,
Which Jag inverter do you have?
I have a generic schematic that I sent to Chris that will work....you may have to cross refer the numbers...unles I can find a way to up,oad pictures from my ipad.,,

[appletree]

Appletree,
Which Jag inverter do you have?
I have a generic schematic that I sent to Chris that will work....you may have to cross refer the numbers...unles I can find a way to up,oad pictures from my ipad.,,

My Inverter is a Jaguar VXS 1.5kw if I remember correctly, its not so much the pendant it self but the programming and relevant connections to the inverter to give no-volt fail safe Regards

[hopefuldave]

Appletree, I don't think the Jag can take pushbuttons (I'm pretty good at reading manuals  ), only maintained (i.e. toggle / latching) switches - the "THR" input could be wired through a NVR though, requiring a poke of a button to reapply the closed connection although that wouldn't ensure the fwd or rev switch wasn't closed? You could put together a pair of interlocked small-signal relays to give pushbutton operation and NVR interlock, fairly cheap and easy BUT the Jag doesn't provide a suitable (i.e. sufficient current) supply, so you'd have the added complication of a transformer (and rectifier if using DC coil relays) and you'd need pushbuttons with dual pairs of contacts - both normally open and normally closed - to ensure you couldn't have forward and reverse energised at the same time (most VFDs will stop in this condition, the Jag's manual isn't clear on this...)

Myself, I have a lathe with a fwd/stop/rev lever on the carriage (with microswitches for fwd and rev) and added a "neutral" microswitch that has to close before I can apply power to the VFD through a contactor. No unexpected starts.