METREL A 1740 User manual

METREL test and measurement accessories:
Calibration Box 5kV
A 1740
Instruction manual
Version 1.1.1, Code no. 20 753 135

Distributor:
Manufacturer:
METREL d.d.
Ljubljanska cesta 77
1354 Horjul
Slovenia
web site: http://www.metrel.si
e-mail: [e-mail]
© 2020 METREL
No part of this publication may be reproduced or utilized in any form or by any means
without permission in writing from METREL.

A 1740 Calibration Box 5kV Table of contents
Table of contents
1Preface ...................................................................................................4
2Safety and operational considerations...............................................4
2.1 Warnings and notes..............................................................................................4
2.2 Markings on the A 1740........................................................................................4
2.3 Standards applied.................................................................................................5
3A 1740 Description................................................................................5
4A 1740 Application................................................................................5
5Maintenance...........................................................................................6
5.1 Cleaning................................................................................................................6
5.2 Service..................................................................................................................6
6Technical specifications.......................................................................6

A 1740 Calibration Box 5kV Preface / Safety and operational considerations
4
1 Preface
It is essential that all measurement instruments are regularly calibrated. For occasional
daily use we recommend an annual calibration to be carried out. When the instrument is
used continuously every day, shorter periodical calibration of the instrument is
recommended.
A 1740 Calibration Box 5kV is optional accessory intended for time-to-time verification
of insulation resistance measurement of the Metrel instruments. This unit contains four
high ohm resistors enclosed in plastic package.
2 Safety and operational considerations
2.1 Warnings and notes
In order to reach high level of operator’s safety as well as to keep the accessory and
equipment undamaged, it is necessary to consider the following general warnings:
Warning on the A 1740 means »Read the Instruction manual with
special care to safety operation«. The symbol requires an action!
If the A 1740 is used in a manner not specified in this Instruction manual or
the manual of target test equipment, the protection provided by the A 1740
and equipment may be impaired!
Read this Instruction manual carefully, otherwise use of the A 1740 may be
dangerous for the operator, for test equipment or for the tested object!
Do not use the A 1740 if any damage is noticed!
Consider all generally known precautions in order to avoid risk of electric
shock while dealing with hazardous voltages!
Service intervention is allowed to be carried out only by a competent
authorized person!
The A 1740 is intended to be applied with Metrel insulation testers!
2.2 Markings on the A 1740
Symbol
Description
Read the Instruction manual with special care to safety operation«.
The symbol requires an action!
The symbol on the Calibration Box 5kV means “Hazardous voltage may
be present at the test terminals!”.
Mark on your equipment certifies that it meets requirements of all
subjected EU regulations.
This equipment should be recycled as electronic waste.

A 1740 Calibration Box 5kV A 1740 Description / A 1740 Application
5
2.3 Standards applied
A 1740 Calibration Box 5kV is manufactured and tested according to the following
regulations, listed below.
Safety
EN 61010 - 1
Safety requirements for electrical equipment for measurement,
control, and laboratory use –Part 1: General requirements
3 A 1740 Description
Outlook of calibration unit
Figure 3.1: Calibration Box 5kV (A 1740)
Legend:
1......................................10 Mconnection stub, (intended for connection of +Rx)
2......................................100 Mconnection stub, (intended for connection of +Rx)
3......................................1 Gconnection stub, (intended for connection of +Rx)
4......................................10 Gconnection stub, (intended for connection of +Rx)
5......................................COMMON connection stub, (intended for connection of –Rx)
4 A 1740 Application
Procedure:
Connect –RX to COMMON connection stub and +Rx to 10 Mconnection
stub.
Set test voltage, press START / STOP key on the instrument and wait until
result becomes stable, then verify indication.
Press START / STOP key again to stop the measurement.
Repeat the same procedure with the rest test values.
The instrument does not require any adjustment if indications are inside the stated
limits.

A 1740 Calibration Box 5kV Maintenance / Technical specifications
6
Warning:
Do not touch Calibration Box 5 kV (A 1740) during measurement! Risk of
electric shock!
Notes:
Pay attention on humidity condition and dirt of the instrument, test leads and
calibration unit due to their high influence on results especially when very high
resistances are measured. It should take an hour or more to adopt the instrument
and calibration unit on new environmental condition.
Keep calibration unit in bubble package when it is not used. Dirt on surface of
calibration unit can significantly reduce the value of reference resistors.
5 Maintenance
Unauthorized person is not allowed to open the A 1740. There are no user replaceable
components inside the calibration unit.
5.1 Cleaning
No special maintenance is required for the housing.
Use soft patch moisten by water or alcohol, and leave the calibration unit to dry totally
after the cleaning.
Warnings:
Do not use liquids based on petrol or hydrocarbons!
Do not spill cleaning liquid over the calibration unit!
5.2 Service
For repairs under warranty, or at any other time, please contact your distributor.
6 Technical specifications
Reference resistors:
Nominal resistance value
Temperature
coefficient
Voltage coefficient
Ratings
10 M
± 200 ppm / °C
< 10 ppm / V
2500 V
100 M
5000 V
1 G
5000 V
10 G
5000 V
General:
Calibration accuracy......................... 1 %
Nominal value accuracy.................... 2 %
Pollution degree................................ 2
Dimensions (W x H x L).................... 113 mm x 39 mm x 62 mm
Case................................................. plastic
Altitude.............................................. 2000 m
Reference temperature range........... 10 C … 30 C
Reference humidity range................. 40 % RH … 60 % RH
Mass................................................. 120 g
Operation.......................................... Indoor use