Friday, December 09, 2005

33 Ohm Resistor

I put the PerkinElmer new thyratron HY-3202 into the x-ray anode control box this morning, but the anode trigger was not well yet. The x-ray anode high voltage was about 100 kV, I guessed there were some place breakdown in advanced. I checked the connectors in the oil tank, all of they looked very well. I pumped the slicon oil into the oil tank and tested the system again. I found there were arcings from the resistor which connected to the step up transformer. I took that resistor to check and found its surface not very good, there are many small holes. Please look at the picture, I marked the holes using the red circle. I think maybe the discharg was from the resistor surface and the ground.
Caution of HY3202 Installation instructions:
1. Keep tube envelope clean. Handle only by base, flange and anode stud. GLOVE SHOULD BE WORN.
2. Don't exert any force on pins, feedtrus or leads. Avoid any bending of pins. Don't carry tube by lead.
3. NEVER reduce reservoir voltage below 5.8 VAC. Tube can be destroyed.
The manufactor was Ward Leonard, model number is KS8512L39A, the resistence measured around 33 Ohm. I have not found this company from Internet. From Ohmite web site, I did not find the similar resistor. I phoned Bill, he said this resistor was used for prevent the high voltage kick back. He remembered that he had some resistors in the electric storge, I will ask Mike to find one next Monday. What if we could not find the resistor? Should I replace it with 40 Ohm or 50 Ohm resistor(I can find them from Ohmite company)? Could you tell me what power is this resistor?

Bill also reminded me that the dirty oil could cause the arcing, or the high voltage cable problems.

1 comment:

Song said...

I found information about KS-8512 L39A resistor at the web site:
Watts: 125
Ohms: 36.5
Maufactor: Memcor(now Ohmite)
Dimension (L x Dia.): 6" x 1 1/8"
Price: $8.85
But I did not find the product from Ohmite company.