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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.
This unit is designed for use from an AC supply of between 200V
min and 264V max. AC rms 50/60Hz. It is not designed to operate
from impedance terminated (IT) systems. If an electrical test is
to be carried out prior to fitting the power supply, it is essential
that the person undertaking this work be a qualified electronics
technician who is fully aware of the hazards of AC line operated
equipment in general and the particular dangers associated with
high voltage switch mode power supplies.
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 AC LINE SUPPLY IS CONNECTED.
AFTER DISCONNECTION FROM THE AC LINE, ALLOW 5 MINUTES 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. For continued
protection against fire hazard replace only with the same type and
rating of fuse. The unit is short circuit proof but care should
be taken that the high voltage is not shorted into one of the control
pin connections.
COMPLIANCE WITH SAFETY STANDARDS
The unit is designed to meet Normalised European Safety Standards
and hence installation of the power supply unit into the equipment
should comply with the following requirements.
a. The external wiring of the Power Supply is part of the fixed
wiring of the equipment.
b. The output is classed as hazardous and must therefore not be
accessible to operators.
c. A PROTECTIVE EARTH must be provided for safety in accordance
with EN61010 Part 1 : 1993 : Clause 6.5.1.
d. An appropriate Mains Isolation switch (Mains on/off) should
be fitted between the AC input of the unit and the equipment electrical
supply plug to allow equipment servicing. To minimise the measured
earth leakage current a double pole isolation switch is recommended.
e. 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.
INSTALLATION
The outputs of these units are considered hazardous in the meaning
of EN61010 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.
Adequate ventilation should be provided to keep the unit cool and
the ventilation slots and fan inlet should not be covered in any
way. The ambient air temperature around the fan inlet must not exceed
45 °C. The unit will operate in any orientation, however it
is not recommended to operate with the side fitted with the fan
as the lowest face. Standard colour coded wires are used for the
AC connections namely brown for live, blue for neutral and yellow-green
for earth. ENSURE that a LOW IMPEDANCE connection is made to PROTECTIVE
EARTH prior to connecting the AC line and neutral. The safety earth
conductor must not contain any switches or fuses.
Under worst case conditions the unit draws a current of 2.2A rms
and any cabling fitted in series with the units mains input supply
cable must be of a suitable type and rating. After switch off, allow
unit to cool for 2 minutes before re-applying power to allow the
inrush current limiting resistors to reset. The unit is fitted with
a 3.15AT 250V HRC AC fuse. Fuses may be fitted externally to the
unit to protect interconnecting wiring etc. but these should be
of the same type and of at least the same rating as that fitted
to the unit.
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 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 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.
GETTING STARTED
PLEASE READ GENERAL, SAFETY & INSTALLATION INSTRUCTIONS BEFORE
OPERATING THIS POWER SUPPLY.
Power supplies are dispatched with internal voltage set potentiometer
at 50V and the internal current trip level set potentiometer at
maximum.
Fit supplied test plug which is linked to select internal current
trip control. Select internal or external voltage control by fitting
appropriate link and connect trip reset circuit or switch.
High voltage output is switched on when Pin 1 is taken low.
When mains power is applied to the unit , it will power up in the
trip condition. Reset by taking pin 1 high (fitted with internal
pull up to +15V).
Trip is reset by taking Pin 1 high.
GREEN LED IS ON WHEN MAINS POWER IS APPLIED.
AMBER LED IS ON WHEN THE UNIT IS TRIPPED.
AMBER LED IS OFF WHEN THE HIGH VOLTAGE OUTPUT IS ON.
a. Apply mains power.
b. Reset trip (pin 1 high).
c. Turn HV on (pin 1 low).
d. Turn up output voltage by either adjusting the internal voltage
potentiometer or increasing the analogue control voltage whilst
monitoring the output voltage.
DO NOT WORK ON HIGH VOLTAGE CIRCUITS CONNECTED TO THIS POWER SUPPLY
UNLESS MAINS POWER IS DISCONNECTED.
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