18.10 Tools incorporating electronic devices shall be so designed that, in the event of a failure in the
electronic equipment, this shall not result in a hazard.
Compliance is checked by operating the tool for 1 min, at a voltage equal to the rated voltage or the mean
value of the voltage range, at no load with the electronic device short-circuited.
The test is then repeated with the electronic device open-circuited.
Following these tests, the tool shall show no damage due to fire, mechanical damage impairing safety and
protection against electric shock.
Where the tool incorporates a device for limiting speed should the electronic device fail to operate, the tool
is considered to have withstood the test when the said speed-limiting device operates during the test.
18.11 Switches or other devices for motor reversal shall withstand the stresses occurring when the sense
of rotation is reversed under running conditions where such a reversal is possible in normal use.
Compliance is checked by the following test.
The tool is operated at a voltage equal to rated voltage, or at the upper limit of the rated voltage range,
at no load; the device for reversing the sense of rotation being in such a position that the rotor rotates in
one direction at full speed.
The direction of the rotation is then reversed, without the device resting in an intermediate
″
off
″
position.
This operation sequence is performed 25 times.
After the test, the switch shall have no electrical or mechanical failure.
18.12 A class I tool employing class II construction (see 5.10) or a class II tool shall be able to operate
under extreme overload conditions without impairing protection against electric shock.
Compliance is checked by the following test on a separate sample.
The sample is connected to a minimum 12 kVA circuit. The tool is loaded to 160 % of normal load current
for either 15 min or until the tool open-circuits or flame appears. If the tool will not operate at 160 %, the
tool is stalled for 15 min or until the tool open-circuits or flame appears. If flames appear, extinguish
immediately with CO
2
extinguisher. The leakage current between live parts and accessible parts,
measured in accordance with clause 13, is monitored throughout the test and after the test until leakage
current has stabilized or decreases. Leakage current shall not exceed 2 mA.
After the tool is cooled to room temperature, an electric strength test per clause 15 is performed between
live parts and accessible parts as follows:
– If a tool does not operate after 15 min, apply a 1 500 V electric strength test.
– If a tool operates after 15 min, apply a 2 500 V electric strength test.
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