Hi all,
I'm wanting to monitor DC bus voltage in a variable frequency drive for a 5hp motor. This drive is 480VAC input so I'm assuming the max voltage is 480*2^.5 which is 678VPP. So, let's design for 700VDC. That is also assuming that the rectifiers in the VFD's are referenced to the other phases. I plan to measure the DC Voltage with a voltmeter sometime soon to really get some accurate data. That is just some background information. Now to my question.
What is a good way to accurately monitor changes on 700VDC with a decent error?
I know I could use a voltage divider, but I'm afraid of error produced by voltage drop in the DC bus by adding a voltage dividing load. And, I also don't want to waste alot of power.
I'm wanting to monitor DC bus voltage in a variable frequency drive for a 5hp motor. This drive is 480VAC input so I'm assuming the max voltage is 480*2^.5 which is 678VPP. So, let's design for 700VDC. That is also assuming that the rectifiers in the VFD's are referenced to the other phases. I plan to measure the DC Voltage with a voltmeter sometime soon to really get some accurate data. That is just some background information. Now to my question.
What is a good way to accurately monitor changes on 700VDC with a decent error?
I know I could use a voltage divider, but I'm afraid of error produced by voltage drop in the DC bus by adding a voltage dividing load. And, I also don't want to waste alot of power.