Ground Continuity Check - GE CT-9800 Technical Publications

GE MEDICAL SYSTEMS
Rev. 1
3. The Recommended Line Analyzer is the Dranitz Model 606-3 (3 channel) with the 101 frequency option or
Dranitz Model 626 with PA 6003, 3-phase AC monitor and the PA 6006 neutral line monitor plug in modules.
Any similar analyzer capable of monitoring mean voltage, surges, or sags, short term impulses, and
frequency drift is adequate.
Monitor at separate intervals
∅A - dB
∅B - dC
∅C - dA
∅A - GND
∅B - GND
∅C - GND
GND - NEUT (if used)
4. From the printouts, ensure that the power supply meets the following criteria:
Phase Balance
+2% max. of lowest phase to phase voltage.
Daily Voltage Variation
+8% to -8% from nominal. Under worst case conditions of line voltage and load.
Voltage Surges
Transient voltage variations caused by external loads must not exceed ± 5% nor exceed 5 cycles
duration and not occur more than 10 times per hour.
Frequency
60 ±0.5 Hz, 50 Hz ±0.5 Hz.
5. Monitor the power lines on an oscilloscope and verify that there is no significant distortion, noise or transients
present. Monitor on both a long and short time base. Generally, harmonics of the third, seventh, and
eleventh derivative will be the most prevalent.
6. Any out of spec conditions should be investigated to identify sources and resolution of problem.

2-3 - Ground Continuity Check

1. Review system grounding diagram Chapter 7, and check that all connections are mechanically secure at both
ends.
2. Using first an AC voltmeter and then an ohmmeter, check that the neutral of each power source for 0 volts to
ground and 0.1 ohms continuity to ground.
4-2-4
CT 9800 QUICK SYSTEM
Direction 18000