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Potentiometer question on 1340GT

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81husky

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#1
I have a new 3 phase 1340GT lathe with Hitachi WJ200 VFD, and have it wired up per Zmotorsports wiring diagram. Everything works as it should, but I'm only getting 8hz max on the VFD display, and as a result no motor speed. The pot is a 1K, 2 watt unit that cost around $12, so not a high ticket item. The frequency changes only at the last bit of rotation of the pot knob, and is opposite of what I would expect. I have the VFD set to 80 hz max per the A004 parameter. Can the pot be causing the problem, or is there something in the VFD programming that I may have missed?
 

Clock work

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#2
Can you use an ohmmeter to verify that you have full impedance end to end on the outside and variable impedance between the wiper and each end?
 

mksj

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#3
Check the pot works with an ohm meter, make sure the connection are to the H, O, L terminals, NOT OI. If the speed goes down as you turn up the pot, then switch the H and L wires.

Check the following parameters:

A001 Frequency source 01 (Control terminal)
A004 Maximum frequency 80
A013 [O] input active range start voltage 0 %
A014 [O] input active range end voltage 100 %
A061 Frequency upper limit 80 (or 0.00 which will deactivate this setting)

A076 PV source 01 ([O] terminal (voltage in))

Recheck the maximum frequency that the decimal place is correct, i.e.something like 80.00
 

81husky

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#4
The pot is 915 ohms from the 2 outer terminals. 874 ohms from center to one side at max, and 942 from center to other side. Parameters were as you recommended with the exception of A014 which was 99. I changed it to 0, and the motor is running same as before. The jog speed and the normal operating speed seem to be the same. Could I have something amiss in the jog wiring?
 

mksj

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#5
The pot should sweep from the middle connection from 0-1K to either side. The value you measured is fine they are usually +/-10% and it makes no difference.
A014 is 100
The jog frequency is typically 6.0 so if you are showing 8.0 Hz, then you may have an error somewhere else. You might need to reset the VFD and reprogram it. See the attached document.
 

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81husky

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#6
I'm not sure exactly what was wrong, but a re-set and re-program has solved the issue. Thank you very much!
 
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