Electrical Testing
CAUTION - testing for electrical safety
should be undertaken by a competent
person and all results recorded. Do not
exceed 1250 volt insulation test duration
of 3 seconds.
1.
Examine the power cable and handle cable for
damage, if the outer insulation shows more than
the slightest of abrasions or the inner conductors
are exposed then the cable must be replaced.
The cables must not be repaired with tape or
insulation sleeve.
2.
Open and check mains plug and interconnecting
socket Ref.24 for condition, loose connections,
damaged wires etc. Ensure that the strain relief
of the power cable plug is correctly secured to the
outer cable insulation.
3.
Open and examine the Switch Housing Ref.11
for loose connections, damaged wires, and
general condition. Pay special attention to any
gaskets, 'O' rings and seals intended to exclude
dust from the switch and switch housing area,
these must be maintained in good condition.
4.
Ensure that the Strain Relief Ref.5 is correctly
secured to the outer cable insulation.
Note: HT8-1.2 Floor Sanders manufactured from
October 1993 starting with Serial Number 00532
(110/120V) and 00779 (220/240V) feature a fully
protected circuit breaker which incorporates 'Low Volt
Protection'. This means that should the mains supply
be interrupted during use the switch will immediately
return to the 'OFF' position to protect the operator.
This feature, by preventing a circuit through the switch
unless mains voltage is present, also prevents a full
insulation (flash) test unless the test instrument has
'
' facility.
If your instrument has this facility then:- replace the
switch cover 'A' taking care to avoid trapping leads
and ensuring that all dust gaskets are correctly
positioned.
Check that the circuit breaker 'ON'
button does not lock in the 'ON' position when
depressed.
The button must only lock 'ON' when
current is present. Before carrying out test ensure that
the motor is connected by the twist lock socket Ref. 24
and that all safety measures have been taken.
(Class 1 Earthed Appliance [U.K.] ) Carry out 'test on
run' procedure.
If your instrument does not have 'test on run' facility
then Continue as follows:-
5.
While you have the switch housing open for
visual inspection remove the circuit breaker
cover 'B' together with the 'low volt coil 'C'(see
below). Do not disconnect or disturb any cables.
The 'low volt coils will remain within the cover 'B'.
The circuit breaker will now lock into the 'ON'
position without current present. Before carrying
out an insulation (flash) test ensure that the motor
is connected by the twist lock socket Ref. 24 and
that all safety measures have been taken.
test on run
9
HT8-1.2 Low Voltage Switch.
CE 0
U AC690V
CSN
EN 60947
START
STO
P
6
4
2
?? ??-??A
TEST
AC 3
SM1-10
5
OEZ
3
1
Cover 'B'
Low Volt Coil 'C'
stays within cover
Gasket
Cover 'A'
Dust Membrane