Section 2-Operation; Introduction; Preparation For Use; Operationon Linepower - Keithley 177 Instruction Manual

SECTION 2
OPERATION
2.1 INTRODUCTION
This section provides information needed for preparation for
use and operation of the Model 177 and Model 1788.
2.2 SAFETY PRECAUTIONS FOR HIGH ENERGY
CIRCUITS
To optimize safety when measuring voltage in high energy
distribution circuits, read and observe the directions in the
following warning.
WARNING
Dangerous arcs of an explosive nature in a
high energy circuit can cause severe
personal injury or death. If the mater is con-
nected to a high energy circuit when sat to
a current range, low resistance range or any
other low impedance range, the circuit is
virtually shorted. Dangerous arcing can
result even when the mater is set to a
voltage range if the minimum safety spac-
ing is reduced.
When making measurements in high energy circuits use test
leads that meet the following requirements:
1. Test leads should be fully insulated.
2. Only use test leads that can be connected to the circuit
(e.g. alligator or spade lugs) for a hands-off measurement.
3. Use test leads that do not reduce the arc protection by
decreasing the voltage spacing between conductors or
terminals.
Use the following sequence when testing power circuits:
1, De-energize the circuit using the regular installed connect-
disconnect device such as the circuit breaker, main switch,
etc.
2. Attach the test leads to the circuit under test. Use ap-
propriate safety rated leads for this application.
3. Set the DMM to the proper function and range.
4. Energize the circuit using the installed connect-disconnect
device and make measurements without disconnecting the
DMM.
5. De-energize the circuit using the installed connect-
disconnect device.
6. Disconnect the test leads from the circuit under test.
2.3 PREPARATION FOR USE
The Model 177 is shipped ready-to-use on line power. The
instrument may also be powered from rechargeable batteries
(when the optional Model 1788 Rechargeable Battery Set is
installed.)
2.4 OPERATION ON LINE POWER
The Model 177 DMM has a three-wire line cord which mates
with third-wire grounded receptacles. Connect the insfru-
ment to AC line power as follows:
1
CAUTION
Connect only to the line voltage selected.
Application of incorrect voltage can
damage the instrument.
Sat the LINE VOLTAGE switch on the back of the instru-
ment to correspond to the line voltage available. Standard
ranges are 105V to 125V and 210V to 250V AC as shown
in Figure 2-l. Optional ranges of 9OV to 11OV and 18OV to
220V AC are also available as shown in Figure 2-2. As in-
dicated on their respective rear panels, the standard line
voltage range instruments use an internal line fuse (F102)
of 1/8A rating and the optional line voltage range instru-
ments use a 3/16A fuse. See Section 5.
WARNING
Ground the instrument through a property
earth-grounded receptacle before opera-
tion. Failure to ground the instrument can
result in savera injury or death in the avant
of short circuit or malfunction.
2. Plug the power cord into a properly grounded outlat.
Operate the Model 177 DMM as described in paragraph
2.7.
2.5 OPERATION ON BATTERY PACK POWER
The Model 177 DMM may also be operated from
rechargeable sealed lead-acid batteries contained in the
optional Model 1788 Battery Pack. The battery pack will
operate the Model 177 DMM for up to six hours. Circuits
within the battery pack will automatically shut down the in-
strument when the battery charge is insufficient to maintain
accurate readings. To install the Modal 1788, refer to Section
5.
2.6 BATTERY CHARGING
The Modal 1788 Battery Pack contains an integral battery
charger. To charge the battery pack, install the battew pack
in the Model 177 DMM as described above and proceed as
follows:
1. Connect the instrument to line power as described in
paragraph 2.4.
2-1