JPH0218719Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a device for switching the working speed of a material handling machine equipped with an electric chain block, an electric trolley, an electric saddle, etc. In a structure including a speed switching relay for changing the speed of a three-phase AC electric motor to which power is applied, a delay operation switch is interlocked and connected to the speed switching relay connected to a manual speed switching switch, and the delay operation switch is The device controls the operation of the power relay, and when the speed of the electric motor is changed by operating the speed switching relay, the electric motor can be restarted by operating the power relay after the inertia rotation of the motor has decreased, and the inertia of the electric motor is controlled. It is possible to prevent an arc short circuit between the poles of the power relay caused by this power generation action accompanying rotation, and to drastically reduce damage such as seizure of the power relay, and to an extent that an arc short circuit between the poles of the power relay does not occur. An object of the present invention is to provide a motor speed control device that can operate a power relay on and off in conjunction with a speed switching relay during low rotation of an electric motor, thereby improving the durability of the power relay and saving overall power consumption. It is something to do.

Embodiments of the present invention will be described in detail below based on the drawings. As shown in FIGS. 1 to 3, a pair of left and right traveling rails 3, 3 are installed approximately parallel to construction supports 1 of a factory etc. through beam members 2, and both ends of an H-shaped steel beam 4 are installed. Electric saddles 5, 5 for connecting and fixing are placed on each rail 3, 3. The saddle 5 is provided with wheels 6 to be fitted on the rails 3 and a reversible electric motor 7 for driving the wheels 6, and the beam 4 is moved back and forth by rotating the motor 7 forward and backward. . Further, the electric trolley 8 is supported by the beam 4 horizontally suspended at an appropriate height, and the trolley 8 is equipped with wheels 9 fitted to the beam 4 and a reversible electric motor 10 for driving the wheels 9. , so that the trolley 8 is moved left and right by rotating the motor 10 in forward and reverse directions. Further, an electric chain block 14 is suspended from the lower ends of the main body frames 13, 13 of the trolley 8 via a support shaft 11 and a hanging metal fitting 12 so as to be able to swing back and forth, and a load chain 16 having a load hanging hook 15. , a reversible electric motor 17 for hoisting and lowering the chain 16; and the motor 17.
control power distribution box 18 and wiring cable 19
The chain block 14 is provided with an operation switch box 20 which is suspended from the box 18 via a switch. Forward and reverse manual operation pushbuttons 21 and 22 are used to move the motor 17 of the chain block 14 in the forward and reverse directions to raise and lower the hook 15, and forward and reverse manual operation push buttons 21 and 22 are used to move the electric motor 10 of the trolley 8 in the forward and reverse directions to move the trolley 8 from side to side. Reverse manual operation push button 2
3 and 24, and forward and reverse manual operation push buttons 25 and 26 for forward and reverse the electric motor 7 of the saddle 5 to move the saddle 5 back and forth. It is configured to carry out cargo handling operations such as lifting and hanging operations, and moving cargo back and forth and left and right using the saddle 5 and trolley 8.

FIG. 4 is a control circuit diagram of the chain block 14. The electric motor 17 of the chain block 14 has a three-phase induction motor structure, and its speed is controlled by a pole number conversion method. for example
The three-phase AC electric motor 17 is provided with input terminals U, V, and W of 6p) and input terminals U', V', and W' of the number of high-speed side poles (for example, 2p). and a power switch 27 connected to the three-phase AC power supplies R, S, and T;
a power supply relay 28 for normal rotation and reverse rotation that connects the power supplies R, S, and T to the motor 17 in normal phase or in reverse phase;
29 and relay switches 30 and 31 for connecting the positive and negative phases of each relay 28 and 29 to each input terminal U, V, W or U', V', W' of the motor 17. A speed switching relay 32 that is connected to either one of the motors 17 and 32 to change the speed of the motor 17 is provided. to the low speed side input terminals U and W of the relay switch 33,
The normally open contacts 33b, 34b of 34 are connected to the motor 17.
are connected to the high-speed side input terminals V′ and W′, respectively.

In addition, after the operation power transformer 35 for driving each of the relays 28, 29, 32, etc. and the relay switches 30, 31 for positive and negative phase connections are turned off, the motor is A delay operation is provided with first and second timers 36 and 37, which are off-delay type delay members that delay the output by the time that the rotation of the motor 17 decreases (for example, 0.2 seconds), and is connected to the transformer 35 via a timer drive power source 38. A relay switch 39, which is a switch, is provided in the speed switching relay 32, and a normally closed contact 39a of the relay switch 39 is connected to the first timer 3.
6, and the normally open contact 3 of the relay switch 39
9b are connected to the second timer 37, respectively.

Furthermore, the above-mentioned forward/reverse manual operation push button 21,
The pushbuttons 21, 22 are equipped with low-speed switches 40, 41 and high-speed switches 42, 43, which are speed changeover manual switches that are operated on and off by means of the pushbuttons 21, 22.
By pressing the button, only the low-speed switches 40 and 41 are turned on, and by further pressing the pushbuttons 21 and 22, the high-speed switches 42 and 43 are turned on while the switches 40 and 41 are on. By returning the push buttons 21, 22, the low speed switches 40, 41 are turned on and only the high speed switches 42, 43 are turned off first, and by returning the push buttons 21, 22, the low speed switches 40, 41 are turned off. A low speed switch 4 and a high speed switch 4 are connected to the push buttons 21 and 22 so that 40 and 41 are also turned off.
0, 41 and 42, 43 are connected. Then, one switch 40, 42 is connected to the transformer 35 via a rising limit switch 44 that regulates the hoisting operation of the load chain 16, and the other switch is connected to the transformer 35 via a descending limit switch 45 that regulates the hoisting operation of the road chain 16. Each switch 4
1 and 43 are connected to the transformer 35, respectively.

Next, the above power supply relay 28 for forward rotation and reverse rotation,
time relay switches 46, 47, and 4, which are switch members that operate 29, that is, time switches;
8 and 49 are provided in the first and second timers 36 and 37, and high-speed operation relays 50 and 51 are connected to the high-speed switches 42 and 43.
0 and 51 are connected to the low speed switches 40 and 41. The normally closed contact 52a of the relay switch 52 is used as the time relay switch 46, the normally closed contact 53a of the relay switch 53 is used as the time relay switch 47, and the normally open contacts 52b, 5 of each relay switch 52, 53 are used as the time relay switch 47.
3b are respectively connected to the speed switching relay 32 via this power supply 54, and the low speed switches 40, 41 are connected to the respective time relay switches 48, 49.
In addition, the power supply relay 28 for normal rotation is connected to the normally open contacts 46a and 48a of each time relay switch 46 and 48.
In addition, a reverse power supply relay 29 is connected to the normally open contacts 47a and 49a of each time relay switch 47 and 49, respectively.

The present invention is constructed as described above, and includes the forward/reverse manual operation push button 2 of the operation switch box 20.
3, 24, 25, and 26 to move the saddle 5 and trolley 8 back and forth and left and right, move the chain block 14 to any desired location, and
When the power switch 27 is turned on, the first timer 36 is activated manually via the relay switch 39. Further, when the forward rotation or reverse rotation manual operation push button 21 or 22 of the switch box 20 is pressed, the low speed switch 40 or 41 is first turned on, and the forward rotation or reverse rotation is activated via the relay switch 52 or 53 and the relay switch 46 or 47. The power supply relay 28 or 29 is energized and the three-phase AC power supply R, S, T is supplied to the low speed input terminals U, V, W of the electric motor 17 via the relay switch 30 or 31 and the relay switches 33, 34. They are connected in phase or in reverse phase, and the motor 17 drives the load chain 16 to be hoisted or lowered at low speed, and the load suspended from the hook 15 is raised or lowered to a desired height at a slow speed.

Furthermore, the forward rotation or reverse rotation manual operation push button 2
When 1 or 22 is pressed more than the above, the high speed switch 42 or 43 is turned on while the low speed switch 40 or 41 is kept on, the speed control relay 50 or 51 is excited, and the relay switch 52 or 53 is switched. At the same time, the speed switching relay 32 is energized via the relay switch 52 or 53, and each relay switch 33, 34 is connected to the high-speed input terminal V', W' of the electric motor 17. At the same time, the relay switch 39 is switched to return the first timer 36 to OFF, and each time relay switch 46, 47 is turned OFF, while the second timer 37 is operated via the relay switch 39, and the electric The time relay switches 48 and 49 are switched with a delay (approximately 0.2 seconds) long enough to reduce the rotation of the motor 17 and prevent an arc short circuit in the relay switches 30 and 31 caused by this power generation. Then, the power supply relay 28 or 29 for forward rotation or reverse rotation is activated via the low speed switch 40 or 41 and the time relay switch 48 or 49, and the three-phase AC power supply R is activated via the relay switch 30 or 31 and the relay switches 33, 34. . To raise or lower a load suspended from 15 to a desired height at a high speed.

Next, when the push button 21 or 22 is returned to its original state and only the high speed switch 42 or 43 is turned off while the low speed switch 40 or 41 is kept on, the speed operation relay 50 or 51 and the speed changeover relay 32 are turned off. At the same time, the relay switches 33 and 34 are connected to the low-speed side input terminals V and W, and the relay switch 39 is switched to the second
The timer 37 is turned off, the time relay switch 48 or 49 is turned off, and the power relay 28 is turned off.
29 is turned off and the first timer 36 is activated again via the relay switch 39 for the time required to prevent the arc short circuit described above (approximately
0.2 seconds), time relay switch 46,4
7 is turned on again, the power supply relay 28 or 29 is excited in the same manner as above, and the electric motor 17 is rotated at a low speed again. When the push button 21 or 22 is further returned to its original position and the low speed switch 40 or 41 is turned off, the power supply relay 28 or 29 is turned off and the electric motor 17 is kept stopped.

In addition, in the above embodiment, the chain block 14
The electric motor 17 of the saddle 5 and the electric motor 10 of the trolley 8 can also be easily controlled to change their speed in the same manner as in the above embodiment. Furthermore, FIG. 5 is an electric circuit diagram showing a modified example, in which the first and second timers 3
A timer power supply switching operation relay 55 is provided for switching a relay switch 39 to switch and connect a timer drive power supply 38 to each relay switch 52, 5.
The relay 55 is connected to the normally open contacts 52b, 53b of 3, and the relay 55 is provided in parallel with the speed switching relay 32 which switches the relay switches 33, 34 at the front stage of this power supply 54. 53, the OFF operation of the relay 32 is delayed by the OFF discharge time of the capacitor 56 connected in parallel to the speed switching relay 32, whereas the almost simultaneous timer power supply is activated in conjunction with the switching operation of the relay switches 52 and 53. The switching operation relay 55 is configured to be turned off. Then, while the high speed switch 42 or 43 is turned on by operating the push button 21 or 22,
When the high speed switch 42 or 43 is turned off by returning the push button 21 or 22,
First, the timer power supply switching operation relay 55 is turned off at the same time as the relay switch 52 or 53 is switched, and the second timer 37 is reset and the power supply relay 2 is turned off.
8 or 29 off, relay switch 30
Or after 31 is turned off, speed switching relay 3
2 is turned off, the relay switches 33 and 34 are switched to the low speed side, and the first timer 36 is activated to rotate at a low speed.

As is clear from the above embodiments, the present invention has a power supply relay 2 for turning on three-phase AC power supplies R, S, and T.
8, 29, and a speed switching relay 32 for changing the speed of the three-phase AC power supply motor 17 to which the three-phase AC power supplies R, S, and T are applied. A delay operation switch such as a relay switch 39 is interlocked and connected to the speed changeover relay 32 connected to the manual speed changeover switch, and the power supply relays 28 and 29 are operated and controlled via the delay operation switch 39. When the speed of the electric motor 17 is changed by operating 32, the electric motor 17 can be reactivated by operating the power relays 28 and 29 after the inertial rotation of the motor 17 decreases, and the inertial rotation of the electric motor 17 It is possible to prevent an arc short circuit between the poles of the power relays 28 and 29 caused by this power generation action, drastically reduce damage such as seizure of the power relays 28 and 29, and prevent an arc short circuit between the poles of the power relays 28 and 29. The power relays 28 and 29 can be turned on and off in conjunction with the speed switching relay 32 during low rotation of the electric motor 17 to the extent that no
The present invention has remarkable effects such as being highly practical as it can improve the durability of the device and reduce the overall power consumption.

[Brief explanation of the drawing]

Fig. 1 is an overall front view showing one embodiment of the present invention, Fig. 2 is a plan view of the same, Fig. 3 is a side view of the same, and Fig. 4 is a front view of the entire embodiment of the present invention.
The figure is an electric circuit diagram of the main part, and FIG. 5 is an electric circuit diagram showing a modified example. 17... Electric motor, 28, 29... Power relay, 32... Speed switching relay, 39... Relay switch (delay operation switch), 40, 41... Low speed switch (speed switching manual switch), 42, 4
3...High speed switch (manual speed switch),
R, S, T...Three-phase AC power supply.

Claims (1)

[Scope of utility model registration request] power relays 28 and 29 for turning on the three-phase AC power supplies R, S, and T; and the three-phase AC power supplies R, S, and T
In a structure including a speed switching relay 32 that changes the speed of a three-phase AC electric motor 17 that applies
The power supply relays 28 and 29 and the speed switching relay 32
The low speed switches 40 and 41 of the manual speed changeover switch that apply this operating power 35 to the power supply relay 2
A first time relay switch 46, 47 for low speed and a second time relay switch 48, 49 for high speed are interposed in parallel between 8, 29, and the low speed switches 40, 41 and the first time relay switch 4 are interposed in parallel.
Relay switch 52 for speed operation between 6 and 47,
53, the speed switching relay 32 is connected to the low speed switches 40, 41 via the speed operation relay switches 52, 53, and the speed operation relay switches 52, 53 are connected to the low speed switches 40, 41.
When the speed control relay switches 52 and 53 are turned on, the operating power source 35 is turned off to apply the operating power source 35 to the power relays 28 and 29 via the first time relay switches 46 and 47, and the speed control relay switches 52 and 53 are turned off when the low speed switch 4 is turned on.
A speed operation relay 50 that is turned on when the high-speed switches 42 and 43 of the speed changeover manual switches 42 and 43 are turned on and turned on and off while the speed changeover relays 2 and 43 are turned on to apply the operation power source 35 to the speed changeover relay 32.
and a first timer 36 for operating the first time relay switches 46, 47 for low speed and the second time relay switches 48, 49 for high speed.
A delay operation relay switch 29 for selectively connecting the first timer 36 and the second timer 37 to the drive power source 38 is interlocked and connected to the speed switching relay 32 for speed switching operation. The first timer 36 and the second timer 37 are switched and operated in conjunction with each other, and the first time relay switch 46, 47 or the second time relay is switched on after a certain period of time after the first timer 36 or the second timer 37 is operated. An electric motor speed control device characterized in that it is configured to turn on switches 48 and 49.