Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: chessie on February 26, 2020, 05:31:49 AM
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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
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have you checked the 0-10V with VDF disconnected
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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 ?
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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.
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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
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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?
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from memory i think i am because i was using the 24v for something else on the machine . i will check later
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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
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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?
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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.
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Thanks for your help .
i have fixed the problem
the earth terminal on the vfd only had the earth connection to the motor and the sheilding of the control cable
i had not connected the earth from the power supply via the filter
i connected it up and it all works fine now with the full 10v and maximum speed
thanks