At the moment, I am working on a device that will be able to measure the out put of a high voltage DC power source with an adjustable output of 0 - -60 kVDC and 0-15 mA (the typical power being 600 Watts at maximum output). However, I will need to be able to monitor the voltage being drawn by the load that it shall be connected to during operation, which will require me to build a voltage measuring probe to get an accurate readout.
Below, I have included a schematic of the apparatus that I am considering to build and will use a list of the parts that I am buying:
The 390 M Ohm resistor shown in the image will be made of 100 3.9 M Ohm resistors connected in series. Each resistor - comprised of a carbon film - has a power rating of 1/4 watt and has a tolerance of 5% (which shall be measured upon arrival). The item may be seen here: https://www.ebay.com/itm/3-9-meg-1-4-watt-5-Carbon-Film-Resistors-100pcs/400005279803?hash=item5d222c303b:g:pbMAAOxygo9Q8MMZ.
The 200 K ohm resistor comprised of 2 resistors in series, the two being "4Pcs 5% 100W 100K Ohm Shell Power Aluminum Housed Case Wirewound Resistors." These resistors can be seen here: https://www.ebay.com/itm/4Pcs-5-100W-100K-Ohm-Shell-Power-Aluminum-Housed-Case-Wirewound-Resistor/183271207134?epid=15020349719&hash=item2aabd0b0de:g:NLsAAOSw3uFbIG-d.
The volt meter used here is a 2.0 G Ohm meter that can handle up to 500 VAC/VDC. The meter may be seen here: https://www.acehardware.com/departments/lighting-and-electrical/electrical-tools/meters-and-testers/3251113.
The entire apparatus will be submersed in mineral oil as a means of electrical insulation (to the exception of the meter-portion of the voltmeter).
With all factors considered, would the apparatus function as intended and how could I further improve it?