PG DRIVES TECHNOLOGY S-DRIVE - INSTALLATION
SK76745/10
10.2 Immunity
The S-Drive controller has been stringently tested for susceptibility to electromagnetic radiation over the frequency range 26 MHz
to 1 GHz. The installations passed the FDA requirements and the requirements of EN12184.
Follow the recommendations in section 10.1.2 to ensure maximum immunity to electromagnetic radiation.
10.3 Electro-Static Discharge (E.S.D.)
There are various international standards currently under development for this aspect of the system’s performance. At present,
most of the standards are specifying the system to be tested to requirements of IEC801-2 Severity Level 3. Tests are carried out at
8kV air discharge (to non-conductive surfaces) and 6kV contact discharge (to conductive surfaces).
E.S.D. produces very fast pulses of electrical energy which, if allowed to enter an electronic system, may cause disruption of
operation or even permanent damage. The S-Drive controller incorporates extensive protection against E.S.D., however, you
should take the following precautions to prevent high levels of energy entering the controller.
The area where E.S.D. is most likely to enter the system is the tiller. Users who have become “charged”, for example by walking on
a nylon carpet, can impart a significant discharge to the scooter via the first point they touch. The best method of protection
against such a discharge is to make all user controls and tiller enclosures non-conductive. Switch manufacturers should be able
to provide appropriate advice and design rules.
Where controls and enclosures are conductive, a low impedance electrical connection to the main mass of the scooter’s
metalwork should be provided. If such a connection is used, it should be kept as short as possible to minimize its electrical
inductance.
If such a low impedance connection cannot be made because of electrical isolation requirements then an alternative electrical
connection should be provided via a varistor. For 24V systems a suitable device is manufactured by Harris, type GE-MOV V82ZA2.
The varistor should be connected between the electrical terminal and battery negative.
Charger socket, battery and motor terminals do not normally require protection.
If you need advice please contact PGDT.
11 Battery Gauge
Refer to Chapter 1 sections 8 and 9 for how to read the battery gauge.
The battery gauge typically starts to flash slowly when the battery voltage falls below 23.3V whilst the scooter is driving on a level
surface. The controller can be programmed so that the low battery flash can commence at different levels. This is achieved via
the parameter Low Battery Flash Level.
For optimum accuracy of the battery gauge and low battery indicator, the controller should be programmed with the
approximate nominal capacity of the scooter battery. However, accuracy is not greatly affected if the programmed type and
capacity do not closely match the battery.
The most important factor affecting the accuracy of the battery gauge is the resistance of the cable and connections between
the battery and the controller. The controller must be matched approximately to the cable resistance of your scooter to make
the battery gauge accurate. Refer to Chapter 3.
As a guide, 2.5mm
2
cable has a resistance of about 8mper meter; 4 mm
2
cable has about 5m per meter and 6mm
2
has
about 3.3m per meter. Circuit breakers and connectors usually account for about 15m.
These values will be chosen at the time the controller is being specified by the scooter manufacturer. Once these values are
decided they are programmed into controllers during manufacture and should never need changing.
If you need advice, contact PGDT.
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