8.5.3.3. Switchboard

In contactless system of ignition the switchboard of 3620.3734 type, either PZE4022, or RT1903 can be installed. It will transform the operating impulses of the contactless sensor to current impulses in primary winding of the coil of ignition.

Fig. 8-27. The scheme for check of the switchboard: 1 — the Om±1 resistor 0,01 of %, not less than 20 W; 2 — the switchboard; 3 — the ignition coil; 4 — a rated sportsman; And — to an oscillograph; B — to the generator of rectangular impulses

The switchboard is checked by means of an oscillograph and the generator of rectangular impulses according to the scheme for fig. 8-27. Output resistance of the generator has to be 100–500 Ohms. An oscillograph it is desirable to apply two-channel. the 1st channel — for generator impulses, and the 2nd — for switchboard impulses.

Fig. 8-28. A form of impulses on the oscillograph screen: And — impulses of tension (U) of the generator; B — impulses of current (I) of the switchboard; t — time of accumulation of current; T — the impulse period; Ти — impulse duration

On the 3 and 6 plugs of the switchboard the rectangular impulses imitating sensor impulses move. Frequency of impulses from 3,33 to 233 Hz, and porosity (the period relation to T impulse duration / Ti, see fig. 6-28) is equal to 3. The maximum tension of Umax — 10 V, and the minimum Umin — no more than 0,4 In (see the oscillogram And in fig. 8-28). At the serviceable switchboard the form of impulses of current has to correspond to the oscillogram of B in fig. 8-28.
For the switchboard 3620.3734 at supply voltage (13,5±0,5) B size of current (I) have to be 7,5-8,5 A. Time of accumulation of current (t) is not normalized.
For the RT1903 switchboard at the same supply voltage and frequency current makes 7-8 A, and accumulation time — 5,5–11,5 ms.
For the PZE4022 switchboard at supply voltage (14±0,3) B and the frequency of 25 Hz the size of current makes 7-9 A, and time of accumulation of current is not normalized.
If the form of impulses of the switchboard is distorted, then there can be interruptions in sparking or it can happen to delay. The engine will overheat and not to develop rated power.

PREVENTIONS
It is impossible to disconnect from the switchboard the plug socket at the included ignition as at the same time on certain sites of the scheme of the switchboard there can be tension to 400 V, and it will be damaged.
It is not allowed to lay wires of low voltage in one plait with wires of high voltage.
It is not allowed to disconnect wires from plugs of the rechargeable battery at the working engine as it can lead to damage of the switchboard.