Sunday, December 25, 2016

Valleylab Force FX Electrosurgical Generator – Test procedure - Checking the Bipolar Output - Checking the Output for the Cut Modes - Checking the Output for the Coag Modes – Medical electronics repair and service

Category: Medical Electronics Repair and Service 

Contents of this article 

  • How to test the Bipolar output
  • How to test the Cut mode
  • How to test the Leakage current 

Valleylab Force FX

Checking the Bipolar Output
1. Verify that the generator successfully completes the self-test as described in Testing the Generator in this section.
2. Connect the test equipment for bipolar output.
a. Connect the two test cables to the Bipolar Instrument receptacle.
b. Pass one test cable through the current transformer and connect the current transformer to the voltmeter.
c. Connect the 100 ohm power resistor across the output jacks at the end of the test cables.
d. Connect the bipolar footswitch to the Bipolar Footswitch receptacle on the rear panel.
3. Press the Precise button and set the bipolar power to 10 watts.
4. Test the output current for the selected Bipolar mode.
a. Press the footswitch pedal and, while activating the generator, note the output on the voltmeter.
b. Release the footswitch pedal.
c. Based on the voltmeter setting and the current transformer you are using, calculate and record the output current.
5. Press the Standard button and repeat step 4.
6. Press the Macro button and repeat step 4.
7. Verify that the generator output for each mode is 316 ± 17 mA rms.
If the output is outside the specified range, calibrate the bipolar output as described in calibration steps 5, 6, 7, and 8. Then repeat this procedure
Check the Output for the Cut Modes
A.
Verify that the generator successfully completes the self-test as described in Testing the Generator in this section.
B. Connect the test equipment for monopolar output.
(1) Connect one test cable to the left jack in the Monopolar 1/CEM
Instrument receptacle. Pass the test cable through the current transformer and connect the current transformer to the voltmeter.
(2) Use a test cable to short the two pins on the Patient Return Electrode receptacle.
(3) Connect the second test cable from the voltmeter to both pins of the Patient Return Electrode receptacle.
(4) Connect the 300 ohm resistor across the output jacks at the end of the test cables.
(5) Connect the monopolar footswitch to the Monopolar 1
Footswitch receptacle on the rear panel of the generator.
C. Press the Pure button.
D. Press the Cut up or down
arrow buttons to set the cut power to 80 watts.
E. Test the monopolar cut output.
(1) Press the footswitch cut pedal and, while activating the generator, note the output on the voltmeter.
(2) Release the footswitch pedal.
(3) Based on the voltmeter setting and the current transformer you are using, calculate and record the output current.
F. Press the Low cut button and repeat step 1.E.
G. Press the Blend button and repeat step 1.E.
H. Verify that the generator output for each mode is 516 ± 37 mA rms.
If the output is outside the specified range, calibrate the monopolar output as described in calibration steps 5, 6, 7, and 8. Then repeat this procedure.
Check the Output for the Coag Modes
A.
Complete items A and B of the previous step, replacing 300 ohm resistor with 500 ohm resistor in item B.4.
B. Press the Desiccate button.
C. Press the Coag up or down
 arrow buttons to set the coag power to 80 watts.
D. Test the monopolar coag output.
(1) Press the footswitch coag pedal and, while activating the generator, note the output on the voltmeter.
(2) Release the footswitch pedal.
(3) Based on the voltmeter setting and the current transformer you are using, calculate and record the output current.
E. Press the Fulgurate button and repeat step 2.D.
F. Press the Med (Fulgurate) button and hold for two seconds. After the tone sounds and the "L" appears on the left side of the Coag display, repeat step 2.D.
G. Press the Spray button and repeat step 2.D.
H. Verify that the generator output for each mode is 400 ± 28 mA rms. If the output is outside the specified range, calibrate the monopolar output as described in calibration steps 5, 6, 7, and 8. Then repeat this procedure.
Checking Low Frequency Leakage Current and Ground Resistance
Check the low frequency leakage current and ground resistance before returning the Force FX-8C generator to clinical use.
Equipment required:
# DVM
# Leakage current tester
Output Receptacles and REM Source Current
1. Set the DVM to AC volts (200 millivolts [mV]) and connect the leakage current test circuit.
2. Turn on the generator.
3. Measure between all the output receptacles (including the Patient
Return Electrode receptacle) and earth ground. Record the largest reading.
4. Determine the leakage current using the conventional
1 microamp (µA) per 1 mV.
5. Verify under normal conditions (ground closed, normal polarity) the leakage current is less than 10 µA.
6. Verify single fault conditions (ground open) the leakage current is less than or equal to 50 µA.
Chassis or Earth Leakage
1. Set the DVM to AC volts (200 mV) and connect the leakage current test circuit.
2. Turn on the generator.
3. Measure between the chassis and earth ground.
4. Determine the leakage current using the conventional 1 µA per 1 mV.
5. Verify under normal conditions (ground closed, normal polarity) the
leakage current is less than 100 µA.
6. Verify single fault conditions (ground open) the leakage current is less than or equal to 300 µA.
Output Receptacles and REM Sink Current
1.
Set the DVM to AC volts (200 mV) and connect the leakage current test circuit.
2. Turn on the generator and connect the end of the leakage current test circuit to mains voltage through a 120 kΩ resistor.
3. Connect the other side of the IEC leakage load to all of the output receptacles (including the Patient Return Electrode receptacle).
4. Determine the leakage current using the conventional 1 µA per 1 mV.
5. Verify the leakage current is less than or equal to 20 µA.
Checking High Frequency Leakage Current
Check the high frequency leakage current and ground resistance before returning the Force FX-8C generator to clinical use. Check the leakage current
# After calibrating the generator
# Every six months.
Equipment required:
# 200 ohm, 250 watt, noninductive resistor
# Current transformer
# True RMS voltmeter (Fluke 8920 or equivalent)
# Bipolar and monopolar footswitches
Checking Monopolar High Frequency Leakage Current
1.
Connect the 200 ohm load from the active accessory through the current transformer to the equipotential ground lug on the rear of the generator.
2. Connect the current transformer to a true RMS voltmeter.
3. Connect a monopolar footswitch to the Monopolar 1 Footswitch receptacle on the rear panel.
4. Activate the footswitch in each Monopolar mode at the maximum control setting. Record the leakage current. If using the leakage table, leakage current should not exceed 150 mA for any mode.
Checking Bipolar High Frequency Leakage Current
1.
Remove the monopolar accessories, and connect the 200 ohm load from one side of the bipolar output through the current transformer to the equipotential ground lug on the rear of the generator.
2. Connect the current transformer to the true RMS voltmeter.
3. Connect a bipolar footswitch to the Bipolar Footswitch receptacle on the rear panel.
4. Activate the footswitch in each mode at maximum control setting.
Record the leakage current. It should not exceed 60 mA for any mode using either the leakage table or short lead configuration..