Megger LT310, Руководство пользователя

Страница: 8 / 25

PREPARATIONS FOR USE (ALL INSTRUMENTS) GENERAL OPERATING INSTRUCTIONS
8
Tests lock
The LOCK
L
indicates when the [Hi] current loop test range is locked
ON.
It is activated by holding down the
L
lock button, and pressing the
[TEST] button. When activated, the [Hi] current loop resistance
measurement will start when the instrument is connected to a voltage.
The test lock remains on for 30 seconds, after which it resets to off.
Test inhibit
The following conditions may cause the instrument to inhibit testing:
Out of range supply voltage
If an out of range voltage or frequency exists on the circuit under test,
or on a very noisy mains supply, testing will be automatically inhibited.
Overheating
Repetitive loop testing generates heat within the instrument. If this
heat becomes excessive the instrument will warn the operator and
prevent further testing until the instrument has had a chance to cool
down.
Fuse Blown
A fuse blown will prevent the instrument from making further tests.
The fuse indicator will be displayed.
Default voltmeter
The default voltmeter automatically operates in all test modes, indicating
connection to a live system.
Auto power-down
To extend battery life the instrument will automatically switch off six
minutes after the last operation.
The instrument can be switched off manually by selecting [OFF] with the
Batteries
The Megger LT300 series instruments are supplied with batteries fitted.
When batteries become exhausted, refer to page 18, battery replacement.
Warning:
Do not switch the instrument on with the battery cover
removed.
Preliminary test lead check
Functional verification
Before each use of the instrument visually inspect the test leads, prods
and crocodile clips to confirm that their condition is good, with no
damaged or broken insulation.