PG DRIVES TECHNOLOGY NEWVSI TECHNICAL MANUAL – INSTALLATION
SK80151-1 31
10.1.1 Motor Suppression
Solder a suitable suppression capacitor between the brush holders of each motor, inside the motor cases. Keep the lead length
as short as possible. We recommend a value of 4n7F 250V AC ceramic. The maximum value you should use is 10nF. A typical
type is Roderstein WY0472MCMCF0K.
For 4 pole motors, a capacitor should be fitted between each pair of brushes.
10.1.2 Cables
You do not need to use screened battery and motor looms, but:
• Keep the length of all wiring to a minimum.
• Make sure the loop area of the wiring is minimized. Route the positive and negative wires to each motor
together.
• Route the battery positive and negative wires together. Where possible, route the battery and motor looms
together.
• Secure the motor and battery looms to the wheelchair frame over as much of their length as is practical.
10.2 Immunity
The newVSI controller has been stringently tested for susceptibility to electromagnetic radiation over the frequency range 26 MHz
to 1 GHz. The test was conducted on a typical wheelchair installation and passed the requirements of EN12184.
Follow the recommendations in section 12.1.2 to ensure maximum immunity to electromagnetic radiation.
11 Battery Gauge
For optimum accuracy of the battery gauge and low battery indicator, the controller should be programmed with the
approximate nominal capacity of the wheelchair 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 wheelchair to make
the battery gauge accurate. The parameter for adjustment is Cable Resistance; refer to Chapter 3 for details on programming
As a guide, 2.5mm
2
cable has a resistance of about 8 milliohms per meter; 4mm
2
cable has about 5 milliohms per meter.
Circuit breakers and connectors usually account for about 15 milliohms.
These values will be chosen at the time the controller is being specified by the wheelchair manufacturer. Like the preset
acceleration rates, once the values for the battery are decided, they are programmed into controllers during manufacture and
should never need changing.
• Controllers are set for a nominal 40amp hour battery and a 40milliohm cable resistance.
If you need advice, contact PGDT
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