Will this be a good replacement for Whirlpool wmh32519hz?

Hello sir, it can not be fit, it needs to remove the original quick connect terminals if you are urgent. I have checked the microwave capacitor for the Whirlpool WMH32519HZ , its part number is W10850446, it is 1.05 mfd capacitor, however its terminals are 1/4 inch standard size(6.35*0.8mm), yet mine is 1.05 mfd 3/16 standard size(4.8*0.5mm), so that it can not meet unless you remove original terminals and use 3/16 size.t you can search "microwave capacitor 1.05 mfd" on amazon, it can shown you relative results, the 1/4 standard size terminal is very obviously bigger on eyesight.

Is this compatible with a Frigidaire microwave?

The brand like Maytag or Frigidaire is only half of the equation what model number do you have might also help research what capacitor you need. More importantly what are the specs on your current capacitor? I was fortunate enough to have my manual with part numbers but the best thing to do is take out your bad capacitor compared to the pictures on this listing especially the connectors the size and shape and lastly the specifications. I needed a capacitor that was rated 1.05 MFD uF, and that’s what this was. SPECS: Voltage:2100 V 50/60Hz AC, Volume: 1.05 MFD uF,Tolerance:±3%. NOTE: The description also warns you that the terminals are 3/16in standard terminal, not tradiontal 1/4in terminals.

Does this have 3 electrical connections on each side?

No, 2 electrical connections on each side.

Will this work with my frigidaire fpbm3077rfb?

Not for it. I have checked the capacitor for frigidaire fpbm3077rfb, its part-number is Capacitor 5304488357, labeled 0.95 mfd, terminal is 1/4 inch standard spade connector. so the the +/- 3% volume requirement, it can not meet for it. you can search "micrwave capacitor 0.95mfd" on amazon, it will show you relative result.