GB2099641A

GB2099641A - Circuit arrangement for the starting of motors by means of electric starter motor

Info

Publication number: GB2099641A
Application number: GB8213026A
Authority: GB
Original assignee: DRESDEN ELEKTROMOTOREN
Current assignee: DRESDEN ELEKTROMOTOREN
Priority date: 1981-06-02
Filing date: 1982-05-06
Publication date: 1982-12-08
Also published as: FR2506848B1; FR2506848A1; DE3211565A1; HU189144B; CS245030B1; GB2099641B; SU1528943A1; DD160551A3

Abstract

A control switch (2) connects the actuating winding (3.3) of auxiliary contactor 3 with voltage source (1). The contacts (3.1 and 3.2) of the auxiliary contactor close simultaneously, connecting both the hold-in winding (4.1) and the series combination of the draw-in winding (4.2) and starter motor (5) with the voltage source. Thus the pinion (6) is moved into engagement with the toothed rim (7) and the starter motor develops reduced torque. When the pinion is fully engaged the switch (4.3) is closed to short-circuit the draw-in winding (4.2) so that the starter motor may develop full torque. The control switch is subject only to low currents as it is not in series with windings 4.1 and 4.2 and may be a semiconductor device. The starting operation may be automated. <IMAGE>

Description

SPECIFICATION Circuit arrangement for the starting of motors by means of electric starter motor The invention relates to a circuit arrangment for the starting of motors by means of electric starter motor, with a two-stage meshing device actuated by an electro-magnet.

Starters are equipped with meshing devices for bringing the pinion into mesh with the toothed rim of the internal combustion engine. Bringing into mesh takes place by the exploitation of the force effect of an electro-magnet. During the meshing operation a circuit arrangement controls the co-operation of electro-magnet and starter motor, so that the teeth of the pinion find gaps between the teeth of the toothed rim, and the pinion is pushed axially into the toothed rim.

In one known circuit arrangement, in a first starting stage a switch connects the actuating winding of an auxiliary contactor and the retaining winding, connected in parallel therewith, of the electro-magnet to a voltage source. The switch is then conducting the currents of both windings.

The switch of the auxiliary contactor thus connects the series connection of a draw-in winding of the electro-magnet and the starter motor to the voltage source. The electro-magnet develops a force which acts axially upon the pinion and at the same time the torque of the starter motor acts upon the pinion. The pinion goes into mesh with the toothed rim. In a second starting stage a further switch, actuated with the electro-magnet, after termination of the meshing operation short-circuits the draw-in winding, so that the starter motor is connected directly to the voltage source and can develop its full torque (TGL 27,735). The fact that in the first and second starting stages it is conducting the current of the actuating winding and of the retaining winding has a disadvantageous effect for the switch. Thus increased expense or the switch is incurred.The switch also requires an increased constructional volume. This has an especially disadvantageous effect when automated or remotely operated starters are used, since the use of modern semiconductor switches as control switches becomes possible only with substantial expense.

The aim of the invention is the elimination of the increased expense and of the increased constructional volume for a control switch of an electric starter motor.

The invention is based upon the technical problem of producing a circuit arrangement which causes a low current through the control switch.

This problem is solved by an auxiliary contactor the actuating winding of which is connected with a control switch. The auxiliary contactor possesses two galvanically separated switches. The first of these switches is electrically connected in series with the retaining winding of an electro-magnet. The second of these switches is electrically connected in series with the draw-in winding of the same electro-magnet and with the starter motor. The two switches are so mechanically connected with one another that they are movable only in common.

In switching on, the control switch connects the voltage source with the actuating winding of the auxiliary contactor, thus the two switches of the auxiliary contactor close and connect the retaining winding of an electro-magnet and the series connection, consisting of the draw-in winding of the electro-magnet and the starter motor, with the voltage source. Under the thereby ensuing force effect of the electro-magnet the pinion can be pushed into the toothed rim. The auxiliary contactor and the electro-magnet then simultaneously initially stress a return spring each.

In a variant according to the invention of the circuit arrangement, an automatic starter control system lies in series with the actuating winding of the auxiliary contactor and/or with the control switch.

In a further variant according to the invention of the circuit arrangement the control switch and/or the automatic starter control system comprise a semi-conductor switch as switching member.

The invention is to be explained in greater detail below by reference to an example of embodiment. The accompanying drawing shows the circuit arrangement.

Three circuits are connected in parallel with one another to the main lead 8, connected with the one pole of the voltage source 1, and the main lead 9 which is connected with the other pole of the voltage source 1. In the first circuit a control switch 2 and the actuating winding 3.3 of the auxiliary contactor 3 are connected in series. The auxiliary contactor 3 possesses two switches 3.1 and 3.2 mechanically connected with one another. In the second circuit the retaining winding 4.1 of the electro-magnet 4 and the switch 3.1 lie in series. In the third circuit the draw-in winding 4.2 of the electro-magnet 4, the switch 3.2 and the starter motor 5 lie in series. In addition, a switch 4.3 of the electro-magnet 4 is connected in parallel with the series connection of the draw-in winding 4.2 and the switch 3.2.The pinion 6 is pushable axially by the electro-magnet into the toothed rim 7 of an internal combustion engine (not shown) and is drivable by the starter motor 5. The auxiliary contactor 3 and the electro-magnet 4 each possess a return spring which restores the basic position as illustrated in the drawing, when the electro-magnetic force effect dies away.

To initiate the starting operation the control switch 2 is closed. The current flux occurring from the voltage source 1 through the main lead 8, the switch 2, the auxiliary contactor 3 and the main lead 9 to the voltage source 1 causes the auxiliary switch 3 to pull up. Thus the switches 3.1 and 3.2 close simultaneously. The current flux through the retaining winding 4.1 and the draw-in winding 4.2 generates a force in the electro-magnet 4 under the action of which the pinion 6 goes axially into mesh with the toothed rim 7. For the starter motor 5 the draw-in winding 4.2 acts like a series resistor, so that the starter motor transmits a reduced torque to the pinion 6. The rotating movement of the pinion 6 facilitates the entry into mesh. When the pinion 6 is completely in mesh with the toothed rim 7, the switch 4.3 shortcircuits the draw-in winding 4.2. The electromagnet 4 is now held in its end position only by the retaining winding 4.1. The starter motor 5 is fed with a current directly from the voltage source 1 , and generates the full torque. After a successful start the switch 2 is opened. The auxiliary contactor 3, under the action of a return spring, opens the switches 3.1 and 3.2. The electromagnet 4 is de-energised and returns under the action of a return spring into the basic position.

The pinion 6 is brought out of mesh with the toothed rim 7.

Claims

1. Circuit arrangement for the starting of motors by means of electric starter motor, especially with a two-stage meshing device actuated by an electro-magnet, characterised in that a meshing winding known per se having an electro-magnet which comprises a retaining winding and a draw-in winding is connected with a voltage source by an auxiliary contactor having a first switch which is connected in series with the retaining winding and a second switch which is connected in series with the draw-in winding.

2. Circuit arrangement according to Claim 1, characterised in that the actuating winding of the auxiliary contactor is connected in series with a control switch and/or an automatic starter control system (not designated further) to the voltage source.

3. Circuit arrangement according to Claim 2, characterised in that the control switch and/or the automatic starter control system comprise a semi-conductor switch as switching member.

4. Circuit arrangement substantially as described with reference to the accompanying drawing.