Ampcontrol Pty Ltd
– ABN 28 000 915 542
IPD USER MANUAL
IPDB014 Version 14
– SEP/2020
Uncontrolled Copy - Refer to Ampcontrol Website for Latest Version
Page 14 of 96
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An introduction to the main protection functions is given in the following subsections. For detailed
information, please refer to the dedicated sections within this document.
4.1.1 Earth Leakage Protection
The IPD monitors the outlet’s earth leakage current through the use of an approved core balance
toroid. This protection function is tested to AS/NZS 2081.3 (2002).
A definite time operating characteristic is provided with independently adjustable trip sensitivity and
time delay.
When a trip is initiated, the IPD will open its MCR output relay, opening the
outlet’s contactor.
For detailed information on the operation of the Earth Leakage protection function, refer to Section 9.1.
4.1.2 Earth Fault Lockout Protection
The earth fault lockout function tests the resistance of the 3 phase lines to earth by applying an
intrinsically safe signal prior to the closure of the main contactor in accordance with AS/NZS 2081.4
(2002). The test is initiated once all starting conditions are met.
If the resistance is above the preset level then an automatic high voltage DC “Insulation Test” to earth
of the cable can be carried out. If the result of the Insulation Test is above the preset resistance level,
the IPD’s MCR relay energises, which in turn closes the main contactor.
A manual “Insulation Test” is also provided as a maintenance/fault finding tool. (When this test is
performed the MCR relay does not close at completion of a healthy test).
The Insulation Test allows cable insulation levels to be trended as an aid to preventative maintenance.
For detailed information on the operation of the Earth Fault Lockout protection function, refer to Section
9.2.
4.1.3 Earth Continuity Protection
The earth continuity function tests for the continuity of the earthing between the outlet and the machine,
via the pilot core in the trailing cable. This is in accordance with AS/NZS 2081.2 (2002). The pilot core
is also used to transfer data when a Remote Termination Unit is used to achieve machine
communication.
For detailed information on the operation of the Earth Continuity protection function, refer to Section
9.3.
4.1.4 Over-Current/Overload Protection
The IPD relay monitors the outlet phase currents via two current transformers. The measured current
allows the IPD to implement over-current, thermal motor overload and phase imbalance protection.
When a trip is initiated, the IPD will open its MCR output relay, opening the outlet’s contactor.
For detailed information on the operation of the Over-Current and Overload protection functions, refer
to Section 10.2.
4.1.5 Short Circuit Protection
In addition to the overload protection functions, the IPD relay uses the currents measured from the two
phase CTs to provide short circuit protection.
The IPD can be set to open either its MCR output or CBR output when a short circuit trip is initiated. In
typical installations the CBR output is used to trip a circuit breaker upstream from the outlet’s contactor.
For detailed information on the operation of the Short Circuit protection function, refer to Section 10.3.
