JPS5941346Y2 - Engine stop switch for generator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an engine stop switch for a generator.

Generally, when starting a generator engine, the generator is rotated by manual operation, and after starting, the output voltage of the generator is intermittent, and the engine is operated by igniting it via an ignition coil, etc. has been done.

On the other hand, when the engine is stopped, the output of the generator is short-circuited by turning on the engine stop switch, thereby stopping the ignition, thereby stopping the engine, that is, stopping the engine.

Conventionally, as such a stop switch, a so-called snap switch is connected to both ends of the generator (coil), which is once turned ON to maintain the ON state, and to turn it OFF, the OFF state is maintained by manually turning it OFF again. Alternatively, a method of connecting an automatically reset normally open switch is used.

However, in the former case, it is common to turn on the switch and forget to turn it off after stopping the engine, so when the engine is restarted, the switch is not changed and the engine often does not start. In the latter case, the startup failure described above can be prevented, but on the other hand, when the engine is stopped, the switch must be held down for about 10 seconds until the engine rotation stops due to engine inertia, which requires manual operation. It has drawbacks such as being troublesome.

The purpose of the present invention is to provide an engine stop switch for a generator that eliminates all of the above-mentioned drawbacks by using an automatically reset normally open switch and a semiconductor switching element. Explain in detail.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, in which 1 is a magnetic generator, 2 is a semiconductor switching element such as a thyristor (hereinafter referred to as thyristor), and is connected in series with a capacitor charging resistor 3. It is connected to both ends of the generator 1.

Reference numeral 4 denotes a charging positive voltage dividing resistor, and 5 and 6 diodes and capacitors, which are connected in series with each other and connected to both ends of the charging resistor 3.

7 is a resistor (for capacitor discharge) connected between the connection point of the diode 5 and capacitor 6 and the control pole (gate) of the thyristor, and SW is the both ends (anode) of the thyristor 2.

An automatic reset normally open switch (hereinafter referred to as the switch) connected to the cathode (between cathodes).

) The above 2 to SW constitute the engine stop switch A.

Next, 8 is a contact breaker connected between the output terminals of the generator 1, and its opening and closing operations are repeated by the rotation of an engine (not shown).

T is an ignition coil, 9 is a discharge gap provided on the secondary side thereof, and these constitute an ignition device B.

Next, the operation of the present invention will be explained using the operation waveform diagram of each part shown in FIG.

During steady operation of the engine, the opening and closing timing of the contact breaker 8 is set in advance depending on the electrode structure of the generator, the shape of the cam, the rotation ratio, etc. In other words, the secondary side of the ignition coil T is opened and closed at the instant of opening and closing. n2 maybe discharge gap 9
generates a spark through the engine to continue operating the engine.

<Operation when the engine is stopped> First, in the case of only the switch SW, when the switch SW is manually turned ON for a predetermined period of time during steady engine operation, this developed electric machine 1 → resistor 4 (or 3) → switch SW
→A current flows through the path of the resistor 3 (or 4) (however, when the contact breaker is OFF), the primary and secondary n1-n2 voltages of the ignition coil T decrease, and the discharge in the discharge gap 9 is stopped.

On the other hand, if the switch SW is automatically reset due to the action of the engine's inertia and turned OFF before the engine rotation decelerates to a predetermined rotation speed, the output voltage will decrease less and the ignition device B will continue to operate until the engine stops. No.

However, in this case, the switch swfJzoN
Then, for example, when the generator output terminal a is positive and the contact breaker 8 is OFF (open), the capacitor 6 is charged through the diode 5 by the voltage generated across the resistor 30 at time t1.

(Fig. 2C) Then, from the time when the voltage across the resistor 3 becomes lower than the charging voltage of the capacitor 6, the charge in the capacitor 6 is discharged through the path of the resistor 7 → the gate of the thyristor 2, the cathode → the resistor 3, and thereby the thyristor 2 During this period, the thyristor 2 is kept in the ON state.

Then, at time t3, when the output terminal a becomes positive again and the contact breaker turns OFF (opened), the thyristor 2
is maintained in the ON state, current flows through the resistor 3 (FIG. 2b), a voltage is generated, and the capacitor 6 is charged again.

This operation is repeated until the engine stops rotating.

That is, even if the switch SW is turned ON for a short time and then automatically turned OFF, the ignition device B can be stopped until the engine rotation stops.

Note that after the engine rotation stops, since the output voltage of the generator is not generated, the capacitor 6 is not charged and discharge proceeds, and after a predetermined time, the gate current of the thyristor 2 is stopped and the thyristor 2 is turned off.

<When restarting the engine> When the engine is started from stopped, the switch SW automatically returns to the OFF state, and the thyristor 2 is also OFF.
Since it is in the F state, it can be reliably started by manual operation.

As described above, in the circuit of the present invention, by providing a simple circuit in the switch SW, the advantages of the conventional snap switch and automatic reset type normally open switch SW are effectively utilized, and the disadvantages are eliminated. Moreover, capacitor 6
By setting the discharge time constant together with the resistor 7, etc., the capacitance is sufficient to supply the gate current until voltage is generated across the resistor 3 in the next positive half cycle, so it can be small (small capacitance). be.

FIG. 3 shows another embodiment of the present invention (the same reference numerals as in FIG. 1 indicate equivalent parts, respectively).

) Constant voltage diode 1 across capacitor charging resistor 3
1, the charging voltage of the capacitor 6 is limited to a predetermined value.

In other words, if the resistance value of the capacitor charging resistor 3 is set to a high value, when the current passing through the resistor 3 is large (during high speed rotation), the voltage drop across the resistor 3 will increase, charging the capacitor 6 to a high voltage and damaging it. There is a risk that this will happen.

On the other hand, when the engine rotates at low speed, the output current of the generator is small.
When the resistance of the resistor 3 is small, the voltage drop is also small, and the capacitor 6 cannot supply the gate current during the holding period of the thyristor 2 until the engine stops.

Therefore, the thyristor 2 turns OFF during the holding period, causing failure to stop the engine.

Therefore, if the resistor 3 is set to have a high or low resistance value as described above, the charging voltage at low speed can be maintained and the above failure can be prevented.

As is clear from the above explanation, the present invention is easy to operate and can surely stop the engine, so it is suitable and practical as a small engine stop switch for engine generators, agricultural machines, outboard motors, etc. The effect is strong.

[Brief explanation of drawings]

1 and 2 are circuit diagrams of one embodiment of the present invention and operation waveform diagrams of each part thereof, and FIG. 3 is a diagram of another embodiment of the present invention. In the figure, 1 is a generator, 2 is a semiconductor switching element,
3, 4, 7 are resistors, 5, 10 are diodes, 6 is a capacitor, 8 is a contact breaker, T is an ignition coil, 9 is a discharge gap, 11 is a constant voltage diode, A
is an engine stop switch, and B is an ignition device.

Claims (2)

[Scope of utility model registration request] (1) In an engine in which the output voltage of a generator is intermittent and ignition is caused via an ignition coil or the like, a semiconductor switching element and a capacitor charging resistor are connected in series to both ends of the generator, and the A diode and a capacitor with the cathode side of the switching element as an anode are connected in series to both ends of the charging resistor, and a connection point between the diode and the capacitor is connected to a control pole of the semiconductor switching element via a resistor, An engine stop switch for a generator, characterized in that an automatic return type normally open switch is connected to both ends of the semiconductor switching element. (2) The engine stop switch for a generator according to claim 1, which is a utility model registration, characterized in that a constant voltage diode is connected in parallel with a capacitor charging resistor.