I have installed this panel meter on my 220 volt wood lathe to provide an external indicator to the frequency being output from a Teco single- to three-phase VFD. The VFD allows me to vary the motor RPMs using a potentiometer.
I have installed this switching 9 volt "wall wart" power supply (there is only 220 volt power in the lathe base) to power the meter. The signal from the VFD to the meter ranges from 0 to 10 volts DC and I have installed the proper resistors on the PMLED (thanks to a topic posted on this forum).
Everything works as expected if I power the PMLED from a 9 volt battery. For example, if the VFD is putting out 30 cycles I get 5 volts (i.e. 30/60). However, if I attach the output from the 9 volt power supply the meter reads 1 and when I turn on the lathe it goes immediately to 19.99 which I guess is the top of the 20 volt range. If I attach a VOM to the power supply output I get 9 volts. I have confirmed all voltages with two separate meters.
I can only guess the power supply is "overdriving" the meter but I have no idea why this is happening and am posting this is hope someone can point me in the right direction. I am a neophyte to this so apologies if the answer is obvious.
I have installed this switching 9 volt "wall wart" power supply (there is only 220 volt power in the lathe base) to power the meter. The signal from the VFD to the meter ranges from 0 to 10 volts DC and I have installed the proper resistors on the PMLED (thanks to a topic posted on this forum).
Everything works as expected if I power the PMLED from a 9 volt battery. For example, if the VFD is putting out 30 cycles I get 5 volts (i.e. 30/60). However, if I attach the output from the 9 volt power supply the meter reads 1 and when I turn on the lathe it goes immediately to 19.99 which I guess is the top of the 20 volt range. If I attach a VOM to the power supply output I get 9 volts. I have confirmed all voltages with two separate meters.
I can only guess the power supply is "overdriving" the meter but I have no idea why this is happening and am posting this is hope someone can point me in the right direction. I am a neophyte to this so apologies if the answer is obvious.