GE ApexPro Service Manual page 102

Ground Continuity Test
Electrical Leakage Tests
4-12
Maintenance: Electrical Safety Tests
Completion of this test is checked by the following steps:
1. Disconnect the DUT (device under test) from the wall receptacle.
2. Connect the negative (–) lead of the ohm meter to the protective earth terminal
(ground pin in power inlet connector) or the protective earth pin in the MAINS
PLUG (ground pin in power cord). Refer to the US 120VAC power cord figure
below.
3. Set the DMM to measure Ohms.
4. Connect the positive (+) lead of the Ohm meter to all exposed metal surfaces on
the DUT. If the metal surfaces are anodized or painted scrape off a small area in
a inconspicuous area for the probe to make contact with the metal.
5. Resistance should read to pass:
‹
0.1 ohm or less to power inlet ground pin
‹
0.2 ohms or less to power cord ground pin
Impedance of Protective Earth Connection
This test, unlike a ground continuity test, will also stress the ground system by using
special ground bond testers e.g. Kikusui (model 872 or TOS 6100) or Associated
Research model HYAMP® Jr. Model 3030D.
This test normally is only required as a manufacturing production test to receive
safety agency compliance UL 609050, CSA 609050-00 (C22.2) and EN60950.
Some country agency's DO require this test after field equipment repairs i.e.
Germany's DIN VDE 0751 standards.
Consult your country/local safety agency if in question.
Compliance is checked by the following steps:
1. A current not less than 10A and not exceeding 25A from a current source with a
frequency of 50 or 60 Hz with a no-load voltage not exceeding 6V is passed for
at least 5 seconds through the PROTECTIVE EARTH TERMINAL or the
protective earth pin in the MAINS PLUG and each ACCESSIBLE METAL
PART which could become LIVE in case of failure in BASIC INSULATION.
2. The voltage drop between the parts described is measured and the impedance
determined from the current and voltage drop. It shall not exceed the values
indicated.
ApexPro Telemetry Server
2001989-178
Ground
Pin
Revision C