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GENERAL
On receipt the unit should be carefully unpacked and inspected
to ensure that no transit damage has occurred. Provided that this
inspection is satisfactory and reveals no evidence of damage then
installation can proceed.
f an electrical test is to be carried out prior to fitting the
power supply, it is essential that the person undertaking this work
has received appropriate technical training to be aware of the hazards
to which that person may be exposed in performing the tests, and
of measures to minimise the risks to themselves, and other personnel.
Metallic or conductive tools should not be used to adjust either
of the potentiometers. The unit has no user serviceable parts and
should not be dismantled.
DO NOT HANDLE OR TOUCH THESE UNITS WHEN THE SUPPLY IS CONNECTED.
AFTER DISCONNECTION FROM THE SUPPLY, ALLOW 30 SECONDS BEFORE HANDLING
SO THAT ALL THE CAPACITORS CAN DISCHARGE. To ensure that the output
is fully discharged, short to ground before touching any high voltage
circuit.
Care should be taken not to operate the unit outside the specified
limits given above, failure to do so may damage the unit.
COMPLIANCE WITH SAFETY STANDARDS
The unit is designed to meet Normalised European Safety Standards
for installation in equipment conforming to EN61010 and hence installation
of the power supply unit into the equipment should comply with the
following requirements.
a. A PROTECTIVE EARTH must be provided for safety in accordance
with EN61010 Part 1:latest: Clause 6.5.1. The case of the units
must be bonded to this protective earth.
b. The output is classed as hazardous and must therefore not be
accessible to operators. The output must be isolated from accessible
circuits by Double Insulation or a protective screen as defined
in EN61010-1.
c. Intended to be installed in an electrical enclosure; the unit
and its input connector should not be accessible to the operator.
Access should be restricted to authorised service personnel only,
with use of a tool. Care should be taken to prevent access to the
interior of the unit and protect against items (e.g. tools or wires)
inadvertently entering the interior of the unit.
d. The unit is not fitted with a fuse and so should be operated
from a current limited supply of <2amp.
INSTALLATION
The outputs of these units are considered hazardous and should
be installed such that they cannot become accessible. The output
should be connected such that the shortest creepage and clearance
path is to a protective earth connection. ENSURE that a LOW IMPEDANCE
connection is made to the unit chassis from the system PROTECTIVE
EARTH. The safety earth (ground) conductor must not contain any
switches or fuses.
Under worst case conditions the unit draws a current of 2A and
any input supply cable must be of a suitable type and rating. The
unit is not fitted with a fuse and so should be operated from a
limited supply. Fuses may be fitted externally to the unit to protect
unit and interconnecting wiring etc. but these should be rated to
prevent nuisance failures. Care should be taken in the design of
the interconnecting wiring within the system to ensure that connectors
with hazardous voltages cannot be connected to accessible circuits.
Ensure that the output is connected to the load prior to operation
of the unit and that a good low impedance high voltage joint is
made. Sharp points on either the high voltage or return joint should
be avoided as this will cause corona which will make the output
appear noisy. In general a tracking distance (creepage distance)
of 25mm (1 inch), per 10kV to earth is advised as a minimum to ensure
no breakdown or corona occurs, a much greater distance will be required
under adverse conditions. Care must be taken not to damage the cable
inner when forming the connections.
During arcing currents exceeding 1000 Amps will flow. It is important
that these currents return to the high voltage power supply by the
shortest possible route using the screen (shield) of the output
cable. Failure to observe this will result in the control terminals
of the unit seeing large voltage spikes during arcing and radiation
of electromagnetic interference.
Adequate ventilation should be provided to keep the unit cool and
the ventilation inlets should not be covered in any way. The ambient
air temperature around the inlet must not exceed 50°C . The
unit will operate in any orientation, however it is not recommended
to operate with the side fitted with the silk-screen as the lowest
face.
OPERATING NOTES
1/ HIGH VOLTAGES ARE DANGEROUS. ENSURE THE OUTPUT IS FULLY DISCHARGED
BY SHORTING TO GROUND BEFORE TOUCHING ANY HIGH VOLTAGE CIRCUIT.
2/ The unit is short circuit proof but care should be taken that
the high voltage cannot be shorted into one of the control pin connections.
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