Raytech USA, Inc. All rights reserved
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SYSTEM DETAILS:
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System Check:
The instrument is Line operated. The system is designed to be used with voltage power sources
(mains power) between 100-250 vac 50/60Hz. The system performs a self check each time that it
is powered on. The user should always visually inspect all connectors, cables and devices to be
measured to avoid any safety issues.
Limitations of Resistance Testing:
The Test system is capable of sourcing 200 amperes DC. The current test leads should have a
total resistance not exceeding 40 milliohms. Beyond the 40 milliohms the test set decreases the
available output current at lowe
r current settings. A warning message may appear:”Use 10 Amp
range”. The system is just letting the user know that the selected current output that the user
wishes to use may not be 100%. However, the system will continue to measure and display a less
accu
rate result. If the message”Rx Too High” or “+++.+”is viewed in the display, then
mandatory range switching must be complied with to continue to test.
Transformer windings:
Use of the MC2 for high inductive winding resistance is not recommended. The inductive
characteristics of transformer winding testing require a long period to saturate the winding to get
a stable reading. In addition, care must be taken when removing test leads such that a voltage
charge does not remain on the winding. Lethal currents might remain and may cause personal
injury and possibly damage the instrument. Specialized test sets with heavy duty discharge
circuits and higher potential compliance voltages and current should be considered for winding
resistance measurements (Raytech WR50 Series of test instruments).
Do not use test probes (MJ04 or other) when testing Inductive loads (Motors, transformers)
or at current levels above 10 amperes. Consult the factory for additional information.
Low Resistance Testing:
The MC2 is an extremely useful device for checking Switch Contacts, SF6 Switchgear, Bus bars,
Splices, Joints, Fuses, Breaker contacts, Rail bonds, and Low inductive windings.
The MC2 utilizes a 4 wire measuring technique. The Two (2) connections on the front plate
marked
+I
& -I are the current leads. The Two (2) connections on the front plate make
+P
& -P
are the Potential or Voltage leads. By connecting a test specimen to the Current leads (See figure
1) and applying the Potential leads across the resistance to be measured. The points where the
potential leads are connected determine the resistance reading.
Figure 1
The test set employs a very simple principle of Ohm’s law: R=V/I
R = Resistance, V = Voltage, I = Current
