Excellent day in the lab.
I got the elevator key copied, so I’ll never get locked out of the lab. I did a successful test of the mechanical relay.
I rearranged the equipment rack to make room for the coil power supply:
Next I mounted the electrical hardware on the sheet aluminum. I started by using a transfer punch to make guides for the drilling. Then I drilled and tapped the holes for M3 bolts:
The first circuit I wired up was the 2 KΩ bleed resistor. Here you can see the bleed resistor wired to the capacitor via a switch. Turning ON the switch bleeds the capacitor:
Next I wired the DC side to the capacitor while minding polarity. Put a voltage meter across the capacitor:
Using the variac I slowly brought up the capacitor to 300V:
Once the capacitor is charged… it holds its charge without much dissipation after the variac goes off.
I was planning to power the relay using this ATX power supply (24V across +12V and -12V):
But during my initial testing it started squeeling and soon blew its fuse!
There was no short circuit that I could see, so perhaps it just died of natural causes?
Anyway… it reminds me: I should fuse the coil power supply before I go much further!