EM TEST (Switzerland) GmbH
CWS500 N1.3 / N1.4
User manual
V 1.01
44 / 47
11.
Maintenance
11.1. General
The generator is absolutely maintenance-free by using solid state semiconductors. The generator uses forced
air cooling. Take care not to cover the cooling slots.
11.2. Calibration and Verification
11.2.1. Factory calibration
Every EM TEST generator is entirely checked and calibrated as per international standard regulations before
delivery. A calibration certificate is issued and delivered along with a list of the equipment used for the
calibration proving the traceability of the measuring equipment. All auxiliary equipment and accessories are
checked to our internal manufacturer guidelines.
The calibration certificate and the certificate of compliance (if available) show the date of calibration.
The EM Test equipment are calibrated in the factory and marked with a calibration
mark. The used measuring instruments are traceable to the Swiss Federal Office of
Metrology.
The calibration date is marked. The validity of the calibration is to the responsibility
of the user’s quality system. Neither the certificate of calibration nor the
corresponding label mark any due date for re-calibration.
Example: Calibration mark
11.2.2. Guideline to determine the calibration period of EM Test instrumentation
Our International Service Departments and our QA Manager are frequently asked about the calibration interval
of EM TEST equipment.
EM TEST doesn’t know each customer’s Quality Assurance Policy nor do we know how often the equipment is
used and what kind of tests are performed during the life cycle of a test equipment. Only the customer knows all
the details and therefore the customer needs to specify the calibration interval for his test equipment.
In reply to all these questions we like to approach this issue as follows :
EM TEST make use of a solid state semiconductor switch technique to generate high voltage transients. A
precious advantage of this technique is the absolute lack of periodical maintenance effort. In consequence
thereof a useful calibration period has to be defined based on two criteria :
-
The first one is the customer’s Quality Assurance Policy. Any existent internal regulation has to be applied at
highest priority. In the absence of such internal regulation the utilization rate of the test equipment has to be
taken into consideration.
- Based on the experience and observation collected over the years
EM TEST recommend a calibration
interval of 1 year
for frequently used equipment. A 2-years calibration interval is considered sufficient for
rarely used test generators in order to assure proper performance and compliance to the standard
specifications.
11.2.3. Calibration of Accessories made by passive components only:
Passive components do not change their technical specification during storage. Consequently the measured
values and the plots stay valid throughout the storage time. The date of shipment shall be considered as the
date of calibration.
11.2.4. Periodically In-house verification
Please refer to the corresponding standard before carrying out a calibration or verification. The standard
describes the procedure, the tolerances and the necessary auxiliary means. Suitable calibration adapters are
needed. To compare the verification results, EM TEST suggests to refer to the waveshape and values of the
original calibration certificate.
All calibrations and verifications are always done without mains supply voltage connected to the coupling
network input.
