[jasminder]

friends,
i have a delta 1hp vfd that i am using to run a 3 phase 1HP motor. The motor rotates, the pot and keypad on the vfd works very well. The parameters are also working but the motor is giving poor torque. If i put my hand on the motor pulley it just stops at any rpms. Even at 1400rpms. I also tried going from 0 to high rpms while holding the pulley but the motor is still very weak. I can hear some noise from the motor but it is not getting hot.

What is wrong with it? the motor has problem or the drive? I am using single phase for power in and three phase out. The motor is running without loads (no belts) with just a small puley.
please help,
jasminder singh

[Al_The_Man]

Do you have the correct motor details entered from the motor label?
Does the drive have auto tuning?
Al.

[M250cnc]

I think the problem is the way the motor if wired.

There should be some links where the cables connect on the motor.

They have two ways of being connected either STAR or DELTA

Maybe Al can even explain it better ?

Phil

Sent from my HTC Desire using Tapatalk

[Al_The_Man]

That might be a point if the motor details were listed and what the connection possibilities are, some are Star/Delta and other dual voltage motors are two sets of star windings, either series or parallel for each voltage supply.
Al.

[jasminder]

friends,
thanks for the support. The motor is wired in delta ( i confirmed it by using a multimeter and checking the continuty of the wires).
the drive does not has auto tuning.
I am surprised that the motor runs with full torque if i run directly on a 3phase power supply and the drive is also giving all the 3 phases ( i checked using a filament bulb that runs on ~60Hz).
I have called the seller of the drive and he says that he will send an expert in few days.

let's see. what's wrong with it
jasminder singh

[jasminder]

friends,
The seller has replaced the VFD with a 3phase in/out VFD and i am able to run lathe with it now.
Now i need some assistance about controlling the speed of the spindle. I have a proximity sensor hooked up to the spindle that works fine (giving active low output). the speed of the spindle is stable within ~4rpms when no load is applied. But when i put my hand on the chuck to put some load (i know it is dangerous a bit) it wents down to ~50 rpms and takes 3 or 4 seconds to recover. I have set the acelleration delays in the VFD to its minimum settings (o.1 second).
Can anybody tell me how to configure pulleys and that PID to get demanded rpms using the "S" word.
Also let me know how many rpms less or more are okay while threading.
i have already tried the mach3 turn manual for help but no luck.

with thanks,
jasminder singh

[Al_The_Man]

Without a feedback from motor to VFD there can be no PID loop.
What modes are available in the VFD? if only speed and torque mode is avail, try it in torque mode.
Al.

[jasminder]

Without a feedback from motor to VFD there can be no PID loop.
What modes are available in the VFD? if only speed and torque mode is avail, try it in torque mode.
Al.

sir,
here is the link to the manual of the VFD. Hope you can help setting up the right parameters.
http://www.delta.com.tw/product/em/d...N_20100514.pdf
I will try using the spindle calibration wizard again hoping for better results this time.

with thanks,
jasminder singh

[Al_The_Man]

It looks like a very comprehensive unit, apparently it does have a loose form of PID loop, they appear to detect the resultant rpm internally?
Al.

[neilw20]

Look at Pr.57 and see if the motor current is set high enough.
Set the display to to show current.
How much is it drawing?
Display is A x.x where x.x is the current being drawn.
What is the rated motor voltage on the name plate?
What model VFD are you using?
What is your mains supply voltage?
The manual is quite comprehensive.
Have you read it?
There are many parameters to set up to make it work correctly.
You need to follow the the manual, and it should work, providing the motor matches what the VFD is set for.
The default VFD settings may not match your motor requirements.
Some configuration is usually required, and from the number of parameters you can set, you will realize it is not trivial.

Good luck.

[jasminder]

It looks like a very comprehensive unit, apparently it does have a loose form of PID loop, they appear to detect the resultant rpm internally?
Al.

sir,
I have absolutely no knowledge about VFD (i saw one first time in my hands).
I know how they work but i have no idea about how fast they response to the given input of 0 to 10V.
I have nothing to do with the PID also. i just want to thread on my lathe. Currently i can control the RPMs within +-10 to the demanded rpms but i want to know if this is good for thread cutting. The rpms keeps increasing and decreasing than the demanded number of rpms and it never holds the rpms even at no load (for example if i enter 1234 in the rpm tab of mach, my spindle runs arround 1225 to 1245)

that's the problem. i have ordered a cnc4pc vfd card today that will be on its way. lets see if it works. Till now i was using my home made ir sensor to convert PWM to volts for the VFD input.

my guess is that the sensor i made is working properly because the freq on the display of the VFD was very stable but i don't know why the rpms were changing (i can fell that from the motor and spindle noise and the rpm tab of mach shows the same).

Gotta wait for a month till the card reaches me after custom clearances ( i hate that word now)
with thanks,
jasminder singh

[jasminder]

Look at Pr.57 and see if the motor current is set high enough.
Set the display to to show current.
How much is it drawing?
Display is A x.x where x.x is the current being drawn.
What is the rated motor voltage on the name plate?
What model VFD are you using?
What is your mains supply voltage?
The manual is quite comprehensive.
Have you read it?
There are many parameters to set up to make it work correctly.
You need to follow the the manual, and it should work, providing the motor matches what the VFD is set for.
The default VFD settings may not match your motor requirements.
Some configuration is usually required, and from the number of parameters you can set, you will realize it is not trivial.

Good luck.

sir,
i was also thinking if the VFD were easy to use things ( i mean so many parameters)
The problem was in my motor. the motor was replaced and drive was changed to a 3phase with 2HP rating (motor is still 1 HP , i wanted to be on safe side this time and may upgrade the motor to 2hp later).
getting a stable rpm with mach3 turn for threading is an issue now.
thanks for help.
jasminder singh

[Al_The_Man]

Also check P 00-09 and see what mode it is in, you may want to try the alternate Vector mode if it is in V/F (volts per hertz).
It also has the feature of using an add on PG card for motor shaft feedback for really precise control or rpm, this method is used in practically all commercial spindles, and is really the only way you are going to get really precise control of an induction motor using a VFD, especially at low rpm's.
Al.

[mike_Kilroy]

sir,
......Currently i can control the RPMs within +-10 to the demanded rpms but i want to know if this is good for thread cutting. ......(for example if i enter 1234 in the rpm tab of mach, my spindle runs arround 1225 to 1245)
jasminder singh

Jasminder, TRY IT! does the thread look good??

if so, then the vfd is working well enough for you! THIS IS LESS THAN 1% SPEED VARIATION on vfd w/o encoder feedback - this is good response and probably makes good threads.

try it and tell us!

If u r indeed in v/hz mode, then you can expect about +/-37 rpm variation since the motor is likely rated 1725rpm and hence you get 0-75rpm variation from no load to motor nameplate rating out of the box. If you are not loading it much, then +/-10rpm is even possible on v/hz drive at your commanded 1234rpm speed. remember, slip of this 75rpm is a constant in v/hz mode IRREGARDLESS OF COMMANDED SPEED; hence, if you command 1725rpm, slip is 75rpm from no load to full load, if you command 1234rpm, slip is 75rpm from no load to full load, if you command 100 rpm slip is still 75rpm from no load to full load.

Assuming this Korean Hitachi replacement vfd is 1/2 as good as the one it replaced (at automation Direct for the same price) you may be able to tweak the vectorless PID parameters to get +/-5rpm but I bet you don't even need that!

[jasminder]

Also check P 00-09 and see what mode it is in, you may want to try the alternate Vector mode if it is in V/F (volts per hertz).
It also has the feature of using an add on PG card for motor shaft feedback for really precise control or rpm, this method is used in practically all commercial spindles, and is really the only way you are going to get really precise control of an induction motor using a VFD, especially at low rpm's.
Al.

sir,
thanks for your help. I am glad that the VFD i have is capable of doing what i want it to do. but actually i am afraid to play with the parameters related to output volts (it may fry the motor or the drive itself). I will try the V/F mode also if it is not already in it. Btw what PG card you are talking about. hope you can put more light on it.

thanks,
jasminder singh

[jasminder]

Jasminder, TRY IT! does the thread look good??

if so, then the vfd is working well enough for you! THIS IS LESS THAN 1% SPEED VARIATION on vfd w/o encoder feedback - this is good response and probably makes good threads.

try it and tell us!

If u r indeed in v/hz mode, then you can expect about +/-37 rpm variation since the motor is likely rated 1725rpm and hence you get 0-75rpm variation from no load to motor nameplate rating out of the box. If you are not loading it much, then +/-10rpm is even possible on v/hz drive at your commanded 1234rpm speed. remember, slip of this 75rpm is a constant in v/hz mode IRREGARDLESS OF COMMANDED SPEED; hence, if you command 1725rpm, slip is 75rpm from no load to full load, if you command 1234rpm, slip is 75rpm from no load to full load, if you command 100 rpm slip is still 75rpm from no load to full load.

Assuming this Korean Hitachi replacement vfd is 1/2 as good as the one it replaced (at automation Direct for the same price) you may be able to tweak the vectorless PID parameters to get +/-5rpm but I bet you don't even need that!

dear mike,
The motor is rated at 1340rpms. It is bacause of a bigger pulley that my spindle can rotate at upto 1725 rpms. (The motor has 5 inch pulley and the spindle has 4 inch)
I will surely try threading with it and post the result.

thanks,
jasminder singh

[Al_The_Man]

sir,
Btw what PG card you are talking about. hope you can put more light on it.

thanks,
jasminder singh

Appendix B page B-20 shows installation of option PG-02.
Al.

[jasminder]

Appendix B page B-20 shows installation of option PG-02.
Al.

sir,
do you mean by the commercial pulse generator cards? Seems to be an expensive route. i guess the pg card will control the motor more precisely because the computer will be eliminated. but how the computer will tell the VFD how many rpm it needs?
any experiences with mach3 and pg cards? I never saw someone using a PG card with a VFD with mach3. I guess i shud wait for the cnc4pc card and it may give me better results.
with thanks,
jasminder singh

[Al_The_Man]

The PG (pulse Generator) card is used to precisely control the Motor via a pulse generator or encoder of some type on the motor shaft, with reference to the input command.
It is separate to any sync signal between spindle and Mach.
Al.

[mike_Kilroy]

friends,
i have a delta 1hp vfd that i am using to run a 3 phase 1HP motor. ..............motor is giving poor torque......
jasminder singh

Do you have the correct motor details entered from the motor label?
Does the drive have auto tuning?
Al.

Jasminder, you recently posted that your motor is rated 1340rpm. so ALs question is even more important now that you say this since 1340rpm is not normal. Normal is either 1450-ish or 1750-ish for 4 pole motors on 50 and 60hz respectively. even 6 pole motors are 950-ish or 1150-ish on 50 and 60hz. so ur 1340 is wierd; if it indeed is an induction motor then it is rated at an off voltage and frequency for some special reason. we sometimes rate 4 pole 1800rpm motors at 2500 or even 5000rpm base speed in order to get higher constant HP speeds out of them. Likewise we sometimes have the 4 pole motor rated at lower than normal voltage at corresponding lower than normal speed in order to get wider constant hp range. bottom line is the delta in no way will run a motor rated 1340rpm perfectly correctly without the nameplate data entered since it is not normal.

I would ask you to carefully write down ALL things written on the motor nameplate, including its mfgr, part no, volts, current, hz, speed, etc etc. or take a picture of it and post that - if you still feel the vfd is not producing the torque or speed regulation you think it should.