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Instruction Sheet
Model 5500A/COIL
50-Turn Current Coil
Introduction
The 5500A/COIL is a 50-Turn Current Coil used as a tool for calibrating clamp-type current meters that operate by two different principles—as current transformers (AC only), and by the Hall Effect (Both AC and DC). It is impractical to calibrate 1000A rated current clamp meters using a 1000A source. How- ever, by using the 50 turns of the 5500A/COIL in conjunction with a current source calibrator one can ef- fectively multiply the current of the current source calibrator by a factor of 50 to support the calibration and verification of these clamp-type current meters.
PWARNING
UNFUSED. Exceeding current and voltage ratings can cause burn or fire hazard.
Using the Coil
Clamp-type current meters operate as current transformers, with differing degrees of magnetic coupling between primary and secondary that vary from meter to meter. The position of the clamp meter with re- spect to the cable also affects the magnetic coupling between primary and secondary of the current trans- former, which causes variation in reading of
the current meter. This is important to under- stand in order to make the most accurate and repeatable measurements. The base of the 5500A/COIL was designed so the current clamp can be centered carefully on the coil, minimizing operator error for best repeatabil- ity. Calibration accuracy to specifications is guaranteed only when proper clamp alignment is made. The clamp current meter should be centered as much as possible on the base dur- ing calibration and verification. If the clamp- type current meter has alignment marks, the alignment marks should align the clamp with the center bundled wire of the 50-Turn 5500A/COIL. (See Figure 1).
Figure 1. Positioning the Clamp
PN 600616 August 1995 Rev.7, 7/08
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