weird happenings regarding MOVs



Published
This is just ONE example of why designing products like this can be really difficult at times !

Bottom blue trace is inverter L1 output... IGNORE that. I should have turned that off.

Scope is synced to the 60Hz AC line, 120VAC into L1 and neutral of the relay board which has a differential amplifier to send a single ended signal to the main JCB B17 control board that converts that top blue signal to digital and internal to that processor, encodes to a PWM signal at 9 kHz to the B17-3 backplane to distribute to the inverter/charger modules.

MOVs are connected to L1 input, L2 input and neutral to CHASSIC which is going NOplace now.
MOVs start out DISCONNECTED and NO relays engaged a the start of video.

NOISY LPF PWM signal because R-C is stuffed into the backplane connector but mainly because differential probe leads suck

Left MOV is L1. Middle MOV is L2 Right MOV is Neutral

I have already fixed one problem where the routing of the L1 V sense op-amp was running underneath the L1 (and other?) copper plane and causing it to be a differentiator.

NOW... What we are seeing on the scope...

Top yellow is PWM to inverters representing the AC1 grid input 10K resistor and 0.47uF cap
This LPF signal from PWM is noisy in a couple of spots because of the awful probe clips on from the differential probe. So that noise a couple of times in the video is not a problem..

Top blue trace is the relay board Op-Amp output that goes into Justin's control board and is stable as a rock as I switch in MOVs and L1 relay.

This top blue signal has also been verified at the A/D input of the processor on the JCB control board that is taking this analog signal and converting it into a 9 kHz PWM signal which goes to the backplane.
Also, verified that the A/D reference voltages on the processor are steady as well as Vcc to the processor at 3.3VDC

L2 relay also makes differences but I only have 2 hands
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Audio
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