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Author Topic: pwm spindle control help needed  (Read 311 times)

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pwm spindle control help needed
« on: February 26, 2020, 05:31:49 AM »
hi ive just put a new motor in my lathe running mach3 turn

its a 1440 rpm 2.2kw 3ph 50hz  motor  (uk)
my vfd is set min hz 20 max 80  0-10v analog v input
 same as the original set up but now 2.2kw instead of the original 1.5kw .

i have a uc400 eth smooth stepper

i think ive changed something in mach3turn
pulley 1 is 0-2300  rpm   (motor and spindle same size pulleys)
the max spindle rpm  will only go 1735 rpm 

i checked the 0-10v input at the vfd and it was only around 6v not 10 hence 60hz not 80
so if i got this right    m3 s2300 should give me 10v at the vfd   = 80hz =2300rpm ish

the breakout board (cnc4you 0-10v) has been fine and produces the 0-10v for the vfd

Any ideas what i should check in the settings as a starter .
regards







Offline TPS

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Re: pwm spindle control help needed
« Reply #1 on: February 26, 2020, 06:08:42 AM »
have you checked the 0-10V with VDF disconnected
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: pwm spindle control help needed
« Reply #2 on: February 26, 2020, 09:45:46 AM »
hi thanks

i took the wires off the vfd
i can now get readings from 0 to 10v  depending on which speed is selected

so is this the break out board or vfd faulty  ?
« Last Edit: February 26, 2020, 09:49:51 AM by chessie »

Offline MN300

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Re: pwm spindle control help needed
« Reply #3 on: February 26, 2020, 11:26:59 AM »
Your initial post reads as if you have only changed the motor, is that the case?

Another item on the list of possible faulty components is the external voltage supply ( 12V?) used by the 0-to-10V circuit. That would be easy to check when the VFD is connected.
Re: pwm spindle control help needed
« Reply #4 on: February 26, 2020, 12:35:31 PM »
i had only changed the motor ,same spec just more kw.
the 0-10 is generated in the breakout board it is not like some stand alone modules .

i presume it just a coincidence or as its ok 0-1730 rpm it may have been like it for a while if i had been using lower rpm for some parts

Offline TPS

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Re: pwm spindle control help needed
« Reply #5 on: February 27, 2020, 03:48:48 AM »
had a quick look to the Manual of the breakout board.
i think you are using this board: https://www.cnc4you.co.uk/Breakout-Board-and-PSU's/Breakout-board-CP0-10V-CNC-4-Axis-with-Charge-Pump

Manual says, supply for the board should 24V-48V. are you using Minimum 24VDC Power supply?
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: pwm spindle control help needed
« Reply #6 on: February 27, 2020, 06:36:48 AM »
from memory i think i am because i was using the 24v for something else on the machine .  i will check later

Re: pwm spindle control help needed
« Reply #7 on: February 27, 2020, 02:08:08 PM »
it was on a 24v psu
but i have a 48v psu that runs the steppers i transferred it to that  but it made no difference.
thanks

Offline TPS

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Re: pwm spindle control help needed
« Reply #8 on: February 28, 2020, 02:56:20 AM »
so it Looks like the bob is not able to deliver the current for the analog Input of the VFD witch is very unusual.

the wiring is like in the Manual?
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.

Offline MN300

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Re: pwm spindle control help needed
« Reply #9 on: February 28, 2020, 08:47:23 AM »
It's unlikely something on the VFD has changed to increase the loading of the signal. However before you spend £50 for a new BOB it would be good to know for sure it's faulty.
You could substitute resistors for the VFD. I would guess the VFD input is equivalent to about a 10K resistor and would expect the BOB to handle a lower value of 5K .
Also you could use your meter to measure the current draw. Improper connection of a meter set to measure current can damage the meter so I don't recommend it unless you have enough experience and understanding to do it safely or know someone who does.

Troubleshooting the board without a detailed schematic is difficult. It maybe a faulty voltage regulator, a poor solder joint, a bad electrolytic capacitor or many other things. Again it would take someone with experience to do this. You could beg cnc4you for the schematic but I doubt they would be willing to share it.

If you do buy a new board the old one could be used to add IO for more limit switches and outputs should you want them.