Cosman G4 Radiofrequency Generator Service Manual (SPI 11291 Rev A)
Section 17
Press the Thermal RF button
Rotate the Output Control knob to minimum
Press the ON button
Record the minimum peak RF voltage displayed on the oscilloscope on the Test Traveler
Increase the output to maximum
Record the maximum peak RF output voltage displayed on the oscilloscope on the Test Traveler
Remove the scope probe
17. Electrical Safety Tests
17.1 HIPOT Testing
Connect a HIPOT to the generator’s AC mains input using the power cord supplied with the unit.
Connect the ground sense lead of the HIPOT to the equipotential connector (or jack) on the back panel
of the generator.
Set the HIPOT to 1800 volts for one (1) second (approximately #34 on the HIPOT setting knob, and
Test Mode B).
Turn HIPOT on.
Warning! Stand clear of the unit under test! Some parts may become live.
Warning! Keep your left hand in left pants pocket during HIPOT testing!
Turn the generators power switch to the ON (or |) position for this test.
Press the START button on the HIPOT. The output will ramp up from zero (0) to its maximum level and
turn off when testing is completed. A failure is indicated by an alarm sounding on the HIPOT.
Turn HIPOT off.
Attach the HIPOT to the patient output connections using the test cable, set the HIPOT for 500 volts
(approximately #20 on HIPOT setting knob, and turn HIPOT on. This is only a test for shorted transient
voltage protectors between the patient outputs and the chassis. The true qualifying test would be 3000v
with the protection devices removed.
Again, Press the START button to initiate the 0ne (1) second test. The output will ramp up from zero (0)
to its maximum level and turn off when the testing is completed.
Turn off HIPOT tester, and disconnect from the generator.
Record Pass/Fail of HIPOT Testing on the Test Traveler
If any of the testing above fails the unit must be returned to Cosman Medical for evaluation and repair.
17.2 Leakage Testing
Plug the Safety Analyzer into an AC power source
Set the AC power source to 132V (for 120V units) or 242V (for 220V units)
This is line voltage plus 10%
Attach the Generator’s power cable to the Test Receptacle of the Safety Analyzer.
Turn Safety Analyzer on. Check that the Generator power switch is still on.
Set Mode switch to measure EARTH leakage current.
Then switch the TEST RECEPTACLE switches to all possible states. The AC leakage current must be
less than 100 microamps.
Record the highest leakage current value on the Leakage Current (Mains) entry on the Test Traveler.
Connect the Output Test Cable from Generator’s Active and Reference jacks (the Black alligator lead) to
any of the Safety Analyzer’s patient lead jacks (or ECG LEADS jacks).
Set MODE switch to LEAD TO GND setting.
Then switch the TEST RECEPTACLE switches to all possible states. The leakage current must be less
than 15 microamps (30 microamps for 220v units).
Note: the standards allow up to 100 microamps, but anything more than shown above is an
indication of a potential problem with the unit.
Record the highest leakage current value on the Leakage Current (Patient) entry on the Test Traveler.
Turn off the Safety Analyzer.
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