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SIP Controllers in Indus-1 and Indus-2
There are about 95 SIP Controllers driving more than 150 SIPs in INDUS machines.
As the SIPs are of different ratings, such as, 270, 140, 70 and 35 l/s, the controllers also have different ratings like, -6.2 KV DC, 1 A, 0.5 A, 0.2 A.
The controllers rated for 1 A, are working in Microtron, TL-2, INDUS-1, TL-3 and INDUS-2.
The controllers rated for 0.5A are working in Booster.
The controllers rated for 0.2 A are working in TL-1.
In INDUS-2, one controller is driving 2 SIPs, simultaneously.
As the vacuum of the INDUS machines must be maintained at its required level, all the time, SIPs and therefore the SIP Controllers must also be ‘ON’ all the time.
SIP controllers of VS1 in INDUS-2 Instrumentation gallery
Specifications:
| Produced by ECIL, Hyderabad |
| Model No: SP 4806A (1000 mA) |
| Output voltage at no load |
6.2 KV DC –ve, ± 5 % |
| Output current at short-circuit |
1000 mA, ±5% |
| Line regulation |
± 3% for ± 10 % line variation |
| Load regulation |
Poor, drooping characteristic |
| Overload protection |
Relay cut-out for pressure set for 10 –5 mbar |
| Display |
3 ½ Digit Digital panel meter for displaying
- Current ranges 1000 mA and 1000 mA Accuracy: ±5%
- Voltage in KV
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| Input |
230 V AC, ± 10%, 50 Hz |
| Weight |
80 Kg , approximately |
| Dimensions |
19 ² x 450 mm x 5U |
Working Principle:
Principle of operation:
The high voltage ferro-resonant transformer utilises the self-saturation of a portion of a magnetic circuit for keeping the maximum output voltage constant in spite of the line voltage variations. The magnetic shunt limits the short-circuit current of the transformer, as well as provides isolation between primary and secondary.
Because of these features, the controller has a poor regulation characteristic.
Brief Circuit description:
The 2.2 KV rms voltage, across the high voltage secondary winding is rectified by a high voltage doubler bridge and filtered by a capacitor filter. The – 6.2 KV DC thus produced is supplied to the pump. The current drawn by the pump, which ranges from 1000 mA to 1 mA, develops voltages across two shunts for two current ranges. This voltage is buffered, amplified and displayed on the Digital Panel Meter provided on the front Panel. The DC high voltage is sensed across a voltage divider and displayed on the same meter. A rotary switch selects either high voltage or current to be displayed.
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