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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.
If 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 any 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,
and will invalidate the warranty.
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. The unit is intended to be installed in an electrical enclosure
and 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 fitted with a resettable semiconductor fuse.
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 0.17A and
any input supply cable must be of a suitable type and rating. 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, very large currents may flow, discharging the load
and cable capacitance, however the unit itself will contribute <5mA.
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.
The ambient air temperature around the unit must not exceed 50°C.
The unit will operate in any orientation.
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.
3/ POWER SUPPLIES WITH THE ‘INTERNAL POT & REF’
OPTION CODE (FP), ARE DISPATCHED WITH INTERNAL POTENTIOMETER SET
TO MAXIMUM. TURN DOWN TO ZERO BEFORE CONNECTING TO 24 VOLT SUPPLY.
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