Valleylab Force FX Testing procedure

Valleylab Force FX periodic testing

• Electrosurgery

The passage of
high frequency
electrical current
through tissue to
create a desired
clinical effect.

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What tests should be done?

1. Output tests in each different mode;

cut, coag and bi-polar.

2. REM high and low trip points

3. RF Leakage test

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Different loads for different modes.

Usually bi-polar mode is tested at 100 ohms load,
cut mode at 300 ohms and coagulation mode at

500 ohms. Measure the current, not the watts. RF
power output circuitry is 1 to 6 N channel
MOSFET’s in parallel. With age and thermal
damage, they begin to fail and the output voltage
drops. Circuitry compensates by increasing the
current thru the MOSFET’s. Current times voltage
equals wattage. Measuring wattage will not detect

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the drop in voltage, but measuring current will
detect the voltage drop. Valleylab specifically
states to test for current under specified load.

3

ESU Math, not quite rocket science

√ Watt setting of ESU / Load setting of tester =

desired test result

Bi-Polar 10 Watts

√ 100 Ω

Coag 30 W

√ 500 Ω

Cut 75W

√ 300 Ω

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= √.1= .316 amp = 316 mA

= √0.06 = .245 A = 245 mA

= √.25 = .5A = 500mA

4

REM testing

•Testing must be done with the middle

pin of the r.e.m. connector present.
Without the pin, the e.s.u. switches to
non r.e.m. circuitry.

•If an e.s.u. is sent to mfr. for repair

with a r.e.m. fault, testing must be done
with the actual patient pad.

•Normal power output testing bypasses

r.e.m. circuitry.

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5

ESU Vocabulary page one

1. Current

The number of electrons moving past a given point per second,
measured in amperes.

2. Current Density

The amount of current flow per unit of surface area; current
concentration directly proportional to the amount of heat generated.

3. Current Division

Electrical current leaving the intended electrosurgical circuit and
following an alternate path of least resistance to ground; typically the
cause of alternate site burns when using a grounded generator.

4. Cut

A low-voltage, continuous waveform optimized for electrosurgical
cutting.

5. Cutting

Use of the cut waveform to achieve an electrosurgical effect that
results from high current density in the tissue causing cellular fluid to
burst into steam and disrupt the structure. Voltage is low and current
flow is high.

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