Starter motor control circuit

Abstract

Provided is a starter motor control circuit capable of easily preventing the induction of a short-circuit current due to a ground fault in the power source line of a starter motor, in which a high current flows. A key switch (13) is connected with a battery (11), and a starter motor starting signal line (19) of a starter motor (18) is connected through a starter relay (16) with a start (ST) of the key switch (13). A protect relay (22) is disposed in a battery line (21) between the battery (11) and the starter motor (18). A ground fault detecting line (24) for detecting the ground fault of the battery line (21) is disposed between the battery line (21) and a controller (14). The controller (14) has a function to restrict the connecting actions of the starter relay (16) and the protect relay (22) when the ground fault of the battery line 21 is detected by a ground fault line (24), even if the key switch (13) is changed to the start (ST).

Description

technical field [0001] The present invention relates to a starter motor control circuit for starting / stopping a starter motor of an engine. Background technique [0002] There is a power supply circuit for a starter motor, which includes: a power supply for a starter motor for an internal combustion engine, a main switch, and a first relay switch that operates in conjunction with the main switch and controls the supply of current to the starter motor for an internal combustion engine, wherein the starter motor The power supply circuit is configured to include: a circuit breaker provided between the power supply and the starter motor for the internal combustion engine; a second relay switch for bypassing the current with respect to the circuit breaker; Turn on the first relay switch, and when the main switch turns to the off direction, turn off the first relay switch, and then turn on the second relay switch when the first relay switch is turned on, the power circuit for the ...

AI Technical Summary

Problems solved by technology

[0006] In construction machinery, since a large current flows through the starter motor, it is not possible to simply use devices such as circuit breakers and fuses for short-circuit protection.

[0007] For example, in the case of the power supply circuit described in Patent Document 1, since the internal resistances of the bypass relay and the circuit breaker do not differ greatly, a large current of about 1000 to 1500 A flows through the circuit breaker even at startup. , causing the circuit breaker to trip unnecessarily

It is difficult to manufacture a bypass relay with a sufficiently lower internal resistance than a circuit breaker

As a countermeasure, it is considered to continuously add resistance to the circuit breaker line, but this will lead to an increase in the size of the circuit breaker

[0008] In addition, in the case of the diagnostic device described in Patent Document 2, even if it is possible to detect in advance the short circuit of the shielding wire due to the intrusion of metal objects in the wiring from the battery to the starter motor, if the treatment is not carried out in a short time, the intrusion of the cable The metal object will also reach the core wire, which has the problem of short-circuiting the core wire

Images