Fluke 5220A, Instruction Manual

Page: 13 / 138

1-1
Section 1
Introduction and Specifications
1-1. Introduction
The Model 5220A is a transconductance amplifier designed to operate as either a stand
alone unit or an extension of the Fluke Model 5100 Series Calibrator. Functionally, the
instrument operates as a precision ac/dc current source for calibrating current shunts
and/or current meters. As the name (transconductance amplifier) implies, the output
current level is a function of an input control voltage. The input/output ratio is established
at 1:1 so that a voltage input in the range of -20 to +20 volts will produce a proportional
current output of -20 to +20 amperes. Input voltages may be either dc or ac levels,
depending on the output requirements. Bandwidth for ac operation is dc to 5 kHz.
Control of the 5220A can be handled locally using front panel controls or remotely by
way of the 5100 Series Calibrator. (The 5100 must be equipped with a Model Y5000
Interface.) Control mode selection is accomplished using two front-panel push button
switches, INPUT and LOCAL. The INPUT switch allows selection of either front or rear
control-voltage input connections. The LOCAL switch is used to recall the 5220A from
remote to local operation.
A series of front panel indicators are used to visually display both the control and
operating status of the 5220A. Control indicators include OPER (operate), STDBY
(standby), FRONT input, REAR input, REMOTE, and LOCAL LOCKOUT. The
combination of lit LEDs indicates the present status of the control mode. Status indicators
include THERMAL CUT-OFF, OVER COMPLIANCE, and OVER CURRENT. When
any one of these indicators is lit, an overload condition has been detected causing the
5220A to switch to standby operation. All indicators are active regardless of the selected
control mode, local or remote.
Current output connections are provided on both the front and rear panels. However, only
one set of terminals is active. Selection of the desired set is accomplished internally and
is, therefore, not considered an operator function. Neither local nor remote operation is
affected by the selection of front or rear output.
Forced-air circulation is incorporated in the 5220A to ensure adequate cooling of the
current output stage. Air is pulled in through a rear-panel filter, passed over the output
stage heat sink, and exhausted through the unit’s side panels.
The 5220A is designed to operate from ac line voltages within the range of 90 V ac to
264 V ac, 50 to 60 Hz. One-of-eight specific voltages (100, 110, 115, 120, 200, 220, 230,
240 V ac +10 %) can be selected to ensure compatibility with the local line voltage. The