The vehicle original power steering is of the v-belt driven hydraulic type. This type of power steering requires relatively a lot of energy to operate. In this conversion application it was decided to use the original 12V starter motor of the petrol engine to drive the power steering pump. In this way the power steering can be switched on only when needed. During driving, the power steering is not really needed, but power steering is useful during parking.
The power steering can be selected (on/off) with a switch mounted on the dashboard. When selected, the power steering switches on for 3 seconds, the moment the accelerator is activated. It resets after this period and can then be re-activated in the same way. When not needed it can be switched off.
The installation of the power steering is shown in the following pictures:
The power steering is switched on using the original solenoid of the starter motor together with a heavy duty switch. The solenoid is switch on/off by using a normal 12V car relay (40A). The car relay is switched on by the three second Timer. The concept is illustrated in the block diagram below.
The circuit diagram of the Timer is shown in the next picture
The heavy duty switch with the solenoide and car relay is shown below