JP3375285B2 - Start / stop circuit for electric motors and engine driven machines - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor applied to, for example, a construction machine and a start / stop circuit of an engine drive machine. 2. Description of the Related Art Conventionally, in a construction machine which can be driven by both an electric motor and an engine, in order to start and stop the electric motor and the engine, when the electric motor is driven, the operation switch and the stop switch for the electric motor are operated. However, when the engine is driven, a method of starting / stopping by operating an engine key switch is generally used. [0003] In this conventional method,
A total of three switches are required: an operation switch for electric motor, a stop switch for the electric motor, and a key switch for the engine. In order to interlock the switches and the hydraulic lock lever, a sequencer is mounted on the body. Therefore, there are many failures due to vibration, and it is expensive. [0004] The present invention has been made in view of such a point, and in a machine that can be driven by either an electric motor or an engine, the starting and stopping of each drive of the electric motor and the engine can be performed by a common switch. It is an object to provide a stop circuit. [0005] The invention described in claim 1 is a circuit for starting and stopping an electric motor driven by an AC power supply, a DC power supply, and an engine driven by the DC power supply. A start / stop circuit, a relay circuit provided between the AC power supply and the start / stop circuit of the electric motor, and a DC power supply and a start / stop circuit of the engine; and a relay circuit provided between the AC power supply and the electric motor by the relay circuit. A power switch for selecting one of a connection to a start / stop circuit and a connection between a DC power supply and a start / stop circuit of the engine; and a power supply selected by the power supply switch to supply or to the selected start / stop circuit. Starting an electric motor and an engine driven machine having a common start / stop switch for starting or stopping one of the electric motor and the engine by stopping supply・ Stop circuit. Thus, in a machine that can be driven by an electric motor and an engine, one of an AC motor and a DC power source selected by a power supply switch and a relay circuit is used to start one of the electric motor and the engine in common.
Start or stop with the stop switch. The present invention will be described below with reference to an embodiment shown in FIGS. 1 to 4. The circuit shown in FIG. 1 corresponds to a construction machine driven mainly by an electric motor but can also be driven by an engine if necessary. The electric motor is driven by an AC circuit, and the engine is Driven by a circuit. An AC power supply 11 is connected to an AC motor circuit 13 via a circuit breaker (NFB) 12, and is further connected to an AC / DC converter 14 for converting AC into DC. Circuit 15 is connected. The DC circuit 15 includes a coil 16 of the relay R1,
Relay R2 coil 17, Relay R3 coil 18, Relay R4 coil 19, Relay R5 coil 20 and Relay R9 coil
With 21. On the other hand, the AC circuit 13 includes an AC power supply 11
The normally closed contact 22 of the relay R2 (hereinafter, the normally closed contact is referred to as “normally closed contact”) 22 is connected to the coil 23 of the relay R6, and the normally open contact of the relay R3 (hereinafter, normally closed contact is referred to as “normally closed contact”). 24) and normally closed contact 25 of relay R9
Is connected to the coil 26 of the relay R7.
The normally open contact 27 of the relay R1, the normally open contact 28 of the relay R1, the normally open contact 29 of the relay R3, and the coil 30 of the relay R8 are connected. Further, a relay is connected to the normally open contact 28 of the relay R1.
Normally open contacts 31 for self-holding of R8 are connected in parallel,
A circuit drawn from between the normally open contact 27 of the relay R5 and the normally open contact 28 of the relay R1 has an electric motor for starting or stopping the electric motor for driving the construction machine via the normally open contact 32 of the relay R8. The motor start / stop circuit 33 is connected. In the DC circuit 15, electric components are connected to the AC / DC converter 14 through a normally open contact 34 of a relay R7.
35, and a start / stop switch 39 is connected via a diode 36, a normally open contact 37 of the relay R6, and a normally open contact 38 of the relay R5. Further, a battery as a DC power supply is provided between the normally open contact 37 of the relay R6 and the normally open contact 38 of the relay R5.
41 and an alternator 42 for charging are connected. The alternator 42 is mounted on the engine,
Although it is an AC generator driven by an engine, it is a charging generator that has a built-in rectifier for converting AC to DC and outputs a DC output to the battery 41. Here, a series of circuits from the alternator 42 to the + side of the battery 41 is an engine-driving charging circuit 61 for charging the battery 41 with DC power supplied from the alternator 42 driven by the engine when the engine is driven.
Is formed. On the other hand, from the AC / DC converter 14 through the diode 36 and the normally open contact 37 of the relay R6, the +
A series of circuits reaching the side form an electric motor driving charging circuit 62 that converts the AC power of the electric motor into a DC power when the electric motor is driven and charges the battery 41. Further, the normally open contact 34 of the relay R7 and the relay
The normally open contact 37 of R6 is an interlock circuit that supplies the voltage generated by the alternator 42 to the battery 41, the electric component 35, and the DC circuit 15 without applying the voltage generated by the alternator 42 to the diode 36 or the AC / DC converter 14. 63 are formed. On the positive side of the battery 41, the normally open contact 43 of the relay R2, the normally closed contact 44 of the relay R7, and the coil 21 of the relay R9
And are connected. Further, a normally open contact 45 of the relay R9 is provided between the electric component 35 and the normally open contact 34 of the relay R7. The start / stop switch 39 is a common key switch capable of starting or stopping each drive of the electric motor and the engine, and is a two-pole rotary switch having an OFF terminal C, a start terminal S and an ACC terminal R. It is also a key switch. A start terminal S of the start / stop switch 39 includes a hydraulic lock switch 46 for fixing a hydraulic actuator such as a construction machine on a hydraulic circuit, a normally closed contact 47 of a relay R2, and a coil 16 of a relay R1. Further, an engine start circuit 49 is connected to a circuit drawn from between the hydraulic lock switch 46 and the normally closed contact 47 of the relay R2 via a normally open contact 48 of the relay R2. On the other hand, the normally open contact 51 of the relay R4, the normally closed contact 52 of the relay R8, and the coil 17 of the relay R2 are connected to the ACC terminal R of the start / stop switch 39. The normally open contact 53 for self-holding of the relay R2 is connected in parallel to the normally open contact 51 of the relay R2, and the normally closed contact of the relay R8 is connected.
In the circuit drawn from between 52 and coil 17 of relay R2,
The engine stop circuit 54 is connected. Further, the normally closed contact 55 of the relay R2 and the coil 18 of the relay R3 are connected to the ACC terminal R of the start / stop switch 39, and a normal switch for switching between an AC power supply and a DC power supply. Power switch 56, an open manual contact
And the coil 19 of the relay R4 are connected. The normally open contact 37 of the relay R6 and the relay
An emergency stop switch 58, which is a normally closed type manual contact, and a coil 20 of the relay R5 are connected to a circuit 57 drawn out from between the normally open contact 38 of R5 and the circuit 57. As described above, on the load side of the start / stop switch 39, the start / stop circuit for starting or stopping both the electric motor and the engine is arranged.
An emergency stop switch 58 is arranged on the power supply side of the stop switch 39. Next, the operation (A) of the illustrated embodiment will be described.
(B) and (C) will be described. (A) First, a method of charging the battery 41 at each drive, regardless of whether the construction machine is driven by an electric motor or an engine, will be described. When the electric motor is driven, or when the circuit breaker 12 is in the on state without driving the electric motor, the relay
The coil 23 of R6 is excited, the normally open contact 37 of the relay R6 is closed, the coil 20 of the relay R5 is excited, and the normally open contact 38 of the relay R5 is closed, so that the AC / DC converter 14 converts AC to DC. The applied DC voltage (approximately 27 V) is applied to the battery 41 and the start / stop switch 39. Therefore, if the voltage of the battery 41 is lower than the DC voltage after the AC / DC conversion (about 27 V),
The battery 41 is charged by the potential difference. On the other hand, when the engine is driven, when the power switch 56 is pressed, the coil 19 of the relay R4 is excited,
The normally open contact 51 of R4 closes, the coil 17 of the relay R2 is excited, the self-holding action of the normally open contact 53 of the relay R2 works, and the normally open contact 43 of the relay R2 closes and the coil 21 of the relay R9 closes.
Is excited, and the normally open contact 45 of the relay R9 is closed. At this time, the normally closed contact 22 of the relay R2 is opened, so that the coil 23 of the relay R6 is de-energized.
Since the normally closed contact 55 of R2 is opened, the coil 18 of the relay R3 is also de-energized, the normally open contact 24 of the relay R3 is opened, and the coil 26 of the relay R7 is de-energized.
Opens. That is, when the engine is driven, the relay R4,
R2 and R9 are in the excited state
), And the relays R6, R3, and R7 are in the de-energized state (hereinafter, this de-energized state is referred to as the "off state"), so that an interlock circuit is formed, and the generated voltage from the alternator 42 The voltage is not applied to the converter 14, but is supplied to the battery 41 and charged. As described above, in a construction machine that can be driven by either an electric motor or an engine, the battery 41 can be charged both when the electric motor is driven and when the engine is driven. (B) Next, with reference to FIGS. 2 to 4, the operation of the start / stop circuit that can start and stop the driving of the electric motor and the engine with the common start / stop switch 39 will be described. . In FIGS. 2 to 4, the excited state (ON state) of each relay R1, R2, R3, R4, R5, R6, R7, R8, and R9 is shown by a black circle, and the excited release state (OFF state) is a white circle. Indicated by First, regardless of whether the electric motor or the engine is driven, the hydraulic operation of the construction machine is fixed by closing the hydraulic lock switch 46. FIG. 2 shows a case in which the electric motor drives a construction machine with the electric motor. (I) The AC power supply 11 is converted into a DC power supply by the AC / DC converter 14 and supplied to the start / stop switch 39. As described above, the relays R6 and R5 are on, and when the start / stop switch 39 is switched to the ACC position, the relays R3 and R7 are turned on and the electric components 35 are connected. (Ii) When the start / stop switch 39 is switched to the start position, the relays R1 and R8 are turned on, power is supplied to the electric motor start / stop circuit 33, and the electric motor starts. (Iii) When the start / stop switch 39 is switched to the off position, the relays R3 and R8 are turned off, and the electric motor stops. FIG. 3 shows a case where the engine is driven and the AC power supply 11 is connected. (I) The AC power supply 11 is converted into a DC power supply by the AC / DC converter 14, and DC power is supplied to the start / stop switch 39 via the relays R6 and R5 in the ON state. When 39 is set to the ACC position, the relays R3 and R7 are turned on. (Ii) When the power switch 56 is pressed to drive the engine, the relays R4 and R2 are turned on,
Relays R3, R6, and R7 are turned off, and power is
At the same time, the relay R9 is turned on, and the electric component 35 is connected to the battery 41. (Iii) When the start / stop switch 39 is switched to the start position, DC power is supplied from the battery 41 to the engine start circuit 49, and the engine starts. When the start / stop switch 39 is switched to an off position (not shown), the power to the engine stop circuit 54 is turned off, and the engine stops. FIG. 4 shows a case where the engine is driven and no AC power is applied. (I) When the relay R5 connected to the battery 41 via the emergency stop switch 58 is turned on, the battery 41
Thus, DC power is supplied to the start / stop switch 39. When this start / stop switch 39 is set to the ACC position, the relay
R3 is turned on. (Ii) When the power switch 56 is pressed to drive the engine, the relays R4 and R2 are turned on.
Relay R3 is turned off, and relay R9 is turned on. (Iii) When the start / stop switch 39 is switched to the start position, DC power is supplied from the battery 41 to the engine start circuit 49, and the engine is started. When the start / stop switch 39 is switched to an off position (not shown), the power to the engine stop circuit 54 is turned off, and the engine stops. As described above, only when the engine is driven, the start-up wait state is set by the power supply switch 56. However, the electric motor drive and the engine drive can be started or stopped by the start / stop switch 39 which is a common key switch. As shown in FIGS. 1 to 4, a hydraulic lock switch 46 is provided at the start position of the start / stop switch 39, so that when the hydraulic lock switch 46 is opened, the lock is released. Since the relay R1 is off and the relay R8 cannot be excited at first, power is not supplied to the electric motor start / stop circuit 33, and power is not supplied to the engine start circuit 49, so that the electric motor and the engine are not supplied. Both drives cannot be started. (C) Next, the operation of urgently stopping the driving of the electric motor and the engine when the engine is driven will be described. When the electric motor is driven, the AC power supply 11
The DC converter 14 converts the DC power into DC power, and supplies the DC power to a start / stop switch 39. When the engine is driven, the DC power is supplied from a battery 41 to the start / stop switch 39. At this time, DC power is also supplied to the emergency stop switch 58 at all times. When the emergency stop switch 58 on the power supply side of the start / stop switch 39 is pressed and opened in an emergency, the coil 20 of the relay R5 is de-energized.
Normally open contact 27 of the DC circuit 15 and normally open contact 38 of the relay R5 of the DC circuit 15.
Open together to shut off the power to the electric motor start / stop circuit 33, and also shut off the power to the start / stop switch 39 at the same time, so that both the electric motor and the engine can be stopped. Operation can be stopped. According to the first aspect of the present invention, in the electric motor and the engine driven machine, one of the AC motor and the DC power source selected by the power supply changeover switch and the relay circuit makes one of the electric motor and the engine one. Start / stop circuit can be started or stopped by a common start / stop switch, and can be inexpensive without the need for a plurality of start / stop switches and a sequencer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an electric circuit diagram showing an embodiment of a start / stop circuit for an electric motor and an engine-driven machine according to the present invention. FIG. 2 is an electric circuit diagram showing an operation of the above circuit when the electric motor is driven. FIG. 3 is an electric circuit diagram showing the operation of the above circuit when the engine is driven and an AC power supply is connected. FIG. 4 is an electric circuit diagram showing the operation of the above circuit when the engine is driven and no AC power is applied. [Description of Signs] 11 AC power supply 33 Electric motor start / stop circuit 39 Start / stop switch 41 Battery 49, 54 as DC power supply Engine start / stop circuit 56 Power supply changeover switches R1, R2, R3, R4, R5, R6, R7, R8, R9 relay

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02N 11/08 E02F 9/00

Claims (1)

(57) [Claims] [Claim 1] A start / stop circuit of an electric motor driven by an AC power supply, a DC power supply, a start / stop circuit of an engine driven by the DC power supply, and an AC power supply A relay circuit provided between the motor and the start / stop circuit of the electric motor and between the DC power supply and the start / stop circuit of the engine. A power switch for selecting one of a connection between a DC power supply and a start / stop circuit of the engine; and an electric motor and an engine for supplying or stopping the supply of the power selected by the power switch to the selected start / stop circuit. And a common start / stop switch for starting or stopping one of the two.