Section 3
TM9211B-A-00
6 November 2013
3-1
3.0
OVERVIEW OF THE 9211B
3.1
General
The Model 9211B is a self-contained 9 range, 4 terminal shunt, for precision current measurements
up to 300 A. The design optimizes a number of important factors such as the effects of self-heating,
temperature coefficient, size, weight, ease of operation and total measuring range.
It provides wide range precise current measuring capability when used with a potentiometer or
digital voltmeter as a readout.
The shunt resistors are mounted in air to minimize size and weight, yet self heating is a negligible
source of error from 20
o
C to 30
o
C. Self-heating has only a small effect for a still wider range of
ambient temperatures. The resistors are made of selected zeranin wire and are non-inductively
wound, up to 1 ampere. The unit consists of nine (9) shunts, of the 4-terminal configuration. Each
shunt provides a 100 mV drop at the nominal rated current. The maximum current rating is 140 % of
nominal for all ranges except the 100 A and 300 A ranges, for which the maximum is
110 % of the nominal current rating.
Figure 3-1 : 9211B Current Terminal Connections
3.2
Operating Instructions
3.2.1
Maximum Current
Determine the maximum current that will be measured. If maximum current to be measured is
unknown, good instrumentation practice would be to approximate it at a value that is certain not to
be exceeded.
As an example, if the current is thought to be between 100 A and 120 A, then the connections
should me made to the 300 A terminals for the measurement.
Summary of Contents for 9211B Series
Page 2: ......
