Ohmeda 3000 - Electrical Safety Checks; Ground Resistance and Leakage Current Tests

4/Calibration and Adjustments
While looping through this test loop the program
also does ram tests, memory checksum, and ADC
calibration tests. If any error occurs an error number
will be displayed on the Elapsed Time display and
the critical alarm will sound for 2 seconds. The pro-
gram will then continue to loop and display any ad-
ditional error numbers. See Section 6 for error code
descriptions.
5. Switch the power “Off”.
6. Set control board test DIP switches to the normal
operating position. (All “Open” or “Off”)
7. Replace the back panel.
Separate Controller Unit Testing
Note: If required the controller unit can be tested
separately from the warmer. The following test load
may be connected in place of a heater assembly.
1. With the power “Off” connect the controller as-
sembly to a test load as follows:
2. Between J17 pin 3 (phase) and J17 pin 1 (heater
N) a 400 watt resistive load for 115 volts.
3. Between J17 pin 3 and J17 pin 2 (alarm light N) a
12 watt resistive load for 115 volts.
4, Between pin 1 and pin 3 of observation light con-
nector a 50 watt resistive load for 12 volts.
I. Oxygen Regulator Check and Adjustment
Check that the output from the regulator is 52 + 2
psig with a 500 cc flow. If adjustment is required
perform the adjustment procedure.
Oxygen Regulator Adjustment Procedure
1. Disconnect the oxygen pipeline connection and
remove the oxygen cylinders.
2. Remove the eight mounting screws for the Oxy-
gen Yoke and Regulator Assembly and then re-
move the assembly.
3. Disconnect the copper tubing from the outlet port
of the regulator.
Note: The regulator must be reset to 52 + 2 psig
with a 500 cc flow passing through it.
4, Attach the special fitting and gauge assembly
(Tool Number 0175-0543-000) to the regulator
outlet, This special tool has a (0.025 in.) orifice to
maintain a 500 cc flow for proper regulator ad-
justment.
5. Adjust the regulator adjustment screw until the
pressure gauge reads 52 + 2 psig.
6. Tighten the adjustment screw lock nut.
7. Remove the special fitting and gauge assembly.
8. Reconnect the copper tubing to the regulator
outlet.
9. Place the Oxygen Yoke and Regulator Assembly
in position on the Infant Wanner System and re-
place the eight mounting screws for the assem-
bly.
J. Electrical Safety Check
Power Cord Inspection
1. Examine the power cord for damage and wear.
2. Examine the power plug for loose or bent pins.
Replace the power cord if the cord or plug is
damaged.
K. Ground Resistance Check
Perform a ground resistance check on the Infant
Warmer System. Use a low range ohmmeter or elec-
trical safety analyzer to measure the resistance be-
tween the ground pin on the line cord plug and the
controller unit. Tug and flex each end of the power
cord during the measurement. The ground resis-
tance must be less than 0.15 ohms. Higher readings
may indicate loose or oxidized connections in the
power cord or the grounding circuits.
L. Leakage Current Tests
Use approved equipment and techniques to test the
unit’s leakage current and ground continuity.
There must be less than 8 microamps on 100v and
120v units (18 microamps on 220v and 240v export
units) measured at the patient probe connection.
Replace the patient probe if necessary.
There must be less than 90 microamps on 100v and
120v units (180 microamps on 220v and 240v units)
measured at an exposed metal surface.
Measure the leakage current under all of the follow-
ing wiring configurations:
1. Normal and reversed polarity.
2. Equipment power “On” and “Off”.
3. Ground open and intact.
Make sure the heater is “On" full during the test.
Set the unit for 100% power in the manual mode.
Use the leakage current tester OMP #0175-2284-000
and digital multimeter (DMM) for the following pro-
cedure:
1. Connection
a. Connect the device under test to the outlet on
the leakage current tester.
b. Make sure the polarity switch on the leakage
tester is in the “Off” Position then plug the line
cord into a grounded 115-120 voit 60 Hz wall out-
let (domestic unit only).
c. Connect the positive lead of the DMM to the
positive + “Meter Out” output.
d. Connect the negative lead of the DMM to the
negative — “Meter Out” output.
e. Set the DMM on the AC millivolt scale.
f. Connect one end of the test cable to the “Exter-
nal Ground" jack on the Leakage Current Tester.
. Use the other end of the test cable (needle probe
tip) to contact the exposed conductive surface of
the device under test.
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