Always a 'fun' day when you get to put on the extra layers

[BreeStephany]

Came in with a coworker after production hours to troubleshoot the 15kVDC 'high side' of a problematic RF generator and got to sweat my **** off in an arc flash suit.

For those of you in the know about proper arc flash PPE, yes, I know I have my balaclava pulled down... it was hot as hell and my goggles fogged, so stopped, got to a safe state and had my coworker power down the machine, verified it was de-energized and stepped away to wipe my goggles out, kept the balaclava down until I was ready to go back at it and my coworker snapped a few photos in the time between.

Determined that the newly installed oscillator is failing to generate RF below full power, so will need to replace the oscillator, burn it in and hopefully get this old ******* of a machine up and running soon.

Its a bit of a crazy machine. 480VAC 3ph 60hz in, transformed to ~7500VAC 3ph 60hz, input voltage to the transformer is changed via SCRs based on the "power" rheostat to control power output. The secondary of the HV tranformer is rectified to DC and stepped up to 15kVDC and the oscillator pulses the DC signal at 4.2Mhz, stored in a capacitor bank / "tank" which then has the ground circuit for the inductive heating coil controlled by an SSR that turns on and off approximately 400~800 times per minute based on the operating speed of the machine so that the inductive field is not present when the machine is inserting parts.

 

[whateg01]

Working on radar CRT always scared the **** out of me. I would check that everything was discharged multiple times before I'd stick my hand anywhere.

 

[BreeStephany]

Working on radar CRT always scared the **** out of me. I would check that everything was discharged multiple times before I'd stick my hand anywhere.

In most cases, this is the case... lock out, ensure incoming power is de-energized and discharge everything on the high voltage side... but I had to verify correct and consistent voltage on the secondary of the HV transformer and verify proper voltage at the rectifier, so I had to place probes live. 25kV hot work gloves, full arc flash gear and had a 25kV mat between myself and the ground.

 

[whateg01]

In most cases, this is the case... lock out, ensure incoming power is de-energized and discharge everything on the high voltage side... but I had to verify correct and consistent voltage on the secondary of the HV transformer and verify proper voltage at the rectifier, so I had to place probes live. 25kV hot work gloves, full arc flash gear and had a 25kV mat between myself and the ground.

Oh, I get it. Sometimes you have to troubleshoot a live circuit. I think the only time I ever had to was in ET A-school. I'm ok with that. I remember all the checks beforehand. Blowing up the rubber gloves to check for pin holes.

 

[WillyBoy]

was in ET A-school

Those were the days. July to October (I think) 1966. Followed the course through the SPS-10 troubleshooting. Then on to Bainbridge MD.

 

[PCustoms]

Whole lotta "nope" in that picture.

Been through the training, had the duffel bag of gear and theoretically knew what I was doing. Whole lotta things had already gone waaaay wrong if I was suiting up.