JPH04121987U - Electric hoist control circuit - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce wear and tear on the contacts of the electromagnetic relay that transmits current to the hoisting motor. [Configuration] When the up switch 9a is turned on, the electromagnetic relay M
When the contact mc1-2 of C1 is turned on, the hoisting motor 4 is driven to rotate forward, and when the lowering switch 9b is turned on, the electromagnetic relay MC2 is turned on.
The contact mc2-2 is closed and the hoisting motor 4 is driven in reverse. When switch 9a (9b) is turned on, timer T1
(T2) operates as a timer, and during this time switch 9a (9
Even if b) is opened, the closed state of contact mc1-2 (mc2-2) is maintained and inching cannot be performed. Timer T1
(T2) is timed up, switch 9a (9b)
Inching can be done by repeatedly turning on and off.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to the control circuit of an electromagnetic hoist, and when the starting current is flowing, the This is a device that prohibits the switching operation.

0002

[Conventional technology]

As shown in FIG. 2, the electric hoist 1 is driven by a traversing motor 2 to move the The wire rope 5 is hoisted and let out by driving the hoisting motor 4. The hook 6 moves up and down. This kind of control of traveling and lifting is carried out via cable 7. This is done by pressing each operation button of the operation push button 9 connected to the hoist body 8. be exposed. The hoist body 8 includes a control box consisting of a sequence circuit for control, and a control box that is hung from the hook 6. There are also load limiters that detect the no-load state, which is a state where no lower load is applied. It is equipped.

0003

[Problem that the idea aims to solve]

The hoisting motor 4 of the electric hoist 1 is composed of an induction motor, and has a starting method. The engine employs direct start. For this reason, when starting, the starting current is 5 to 6 times the rated current. Current flows. In addition, at the beginning of hoisting a slinged load and at the end of unwinding, inching ( (jinging) is often performed violently. This inching is the starting voltage sent to the hoisting motor 4. This is done by turning the current ON and OFF in a short time using an electromagnetic relay. this If such inching is performed at the time of starting, the starting current will be 5 to 6 times the rated current for a short period of time. Frequent inching will shorten the life of the electromagnetic relay as it turns on and off between I end up losing it.

0004 In view of the above-mentioned conventional technology, the present invention prohibits inching during the starting time to prevent electromagnetic connection. It provides an electric hoist control circuit that can extend the life of the contactor. Ru.

[0005]

[Means to solve the problem]

The configuration of the present invention that solves the above problems is that when the switch is turned on, the motor drive The electromagnetic relay is energized and its contact is closed, and the hoisting motor is activated through the closed contact. The electric hoist control circuit supplies current to the hoist motor to drive the hoist motor. On the road, Once the switch is turned on, the motor will not operate regardless of whether the switch is turned on or off. The electromagnetic relay for driving is held in an excited state for a certain period of time, and the switch is turned off after a certain period of time. To allow the electromagnetic relay for motor drive to be energized and demagnetized in response to the closing and opening of It is characterized by being equipped with a relay circuit.

[0006]

[Effect]

During the startup period, the timer operates and the timer is activated regardless of whether the up/down switch is on or off. Inching is prohibited by energizing the electromagnetic relay that supplies current to the hoisting motor. be done. When the timer expires, the rise/fall switch is turned on/off. The current can be supplied and stopped to the hoisting motor, and inching can be performed.

[0007]

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 shows the electromagnetic hoist. 3 shows a portion of the control sequence circuit that is involved in the lifting motion related to the present invention. figure 1, the three-phase power supply 10 is a commercial power supply (50Hz or 60Hz), and Three-phase power is supplied through the limit switch LSII. Hoisting motor 4 is three-phase It is an induction motor, and when it reverses, it winds up and reverses. Unwind by. The hoisting brake 11 applies the brake when demagnetized, When energized via the rectifier 12, the brake is released. Also, the upper limit switch The switch LSI opens when the hook 6 rises and reaches the upper limit position, and The material is added. Furthermore, the operation push button 9 has an up switch 9a and a down switch 9b. It is equipped.

[0008] Furthermore, in order to perform sequence control, electromagnetic relay MC1 and its contacts mc1-1, mc1-2, mc1-3, electromagnetic relay MC2 and its contacts mc2-1, mc2- 2, mc2-3, electromagnetic relay X1 and its contacts x1-1, x1-2, electromagnetic relay X2 and its contacts x2-1, x2-2, timer T1 and its contacts t1-1, t1 -2, a timer T2 and its contacts t2-1 and t2-2 are provided. Timer T The setting time 1 is the time when the current value reaches the rated value after starting to supply current to the hoisting motor 4. The time is set to be the same as the time it takes (for example, 0.4 seconds). When setting Tamai T2 The time period is slightly longer than the time set by timer T1, and timer T2 is set to the timer T1. Acts as a backup.

[0009] When the up switch 9a is turned on, the electromagnetic relays MC1 and X1 are energized. electromagnetic Excitation of relay MC1 opens contact mc1-1 and closes contact mc1-2. The hoisting motor 4 is driven to rotate forward, and the hoisting brake 11 is activated by closing the contact mc1-3. is canceled. This causes the hook 6 to rise. Also, the excitation of electromagnetic relay As a result, self-holding contact x1-1 is closed, contact x1-2 is closed, and the tie is closed. The timer T1 and T2 start timer operation. Timers T1 and T2 are operating as timers. Even if the rise switch 9a is turned off, x1-1 → t2-1 → t1-1 → Current is supplied to the electromagnetic relays MC1 and X1 through the LSI→mc2-1. Therefore Inching is not possible during this timer operation period, that is, the period when the starting current is flowing. . Therefore, without turning on and off a large starting current at contacts mc1-2, contact m The life of c1-2 is extended.

0010 When timer T1 times out, contact t1-1 opens, so the rising switch When 9a is repeatedly turned ON and OFF, electromagnetic relay MC1 is in the excited state. The demagnetization state is repeated, and the contacts mc1-2 are repeatedly turned ON and OFF, and inching is not possible. Wear. At this time, the current value flowing through the hoisting motor 4 is a steady value, so Even if the contacts mc1-2 are repeatedly turned on and off, there is little wear and tear. In addition, timer T2 will time up following timer T1, so even if one of the timers fails, , it is possible to shift to a state where inching operation is possible.

[0011] When the lowering switch 9b is turned on, the electromagnetic relays MC2 and X2 are energized. electromagnetic Due to the excitation of relay MC2, contact mc2-1 opens and contact mc2-2 closes. The hoisting motor 4 is driven in reverse, and the hoisting brake 11 is activated by closing contact mc2-3. is canceled. As a result, the hook 6 descends. Also, excitation of electromagnetic relay As a result, self-holding contact x2-1 is closed, contact x2-2 is closed, and the tie is closed. The timer T1 and T2 start timer operation. Timers T1 and T2 are operating as timers. Even if the lowering switch 9b is turned off, x2-1 → t2-2 → t1-2 → Current is supplied to electromagnetic relays MC2 and X2 through mc1-1. Therefore, this Thailand Inching is not possible during the main operation period, that is, during the period when the starting current is flowing. Therefore Contact mc2-2 does not turn on and off a large starting current at contact mc2-2. lifespan is extended.

0012 When timer T1 times out, contact t1-2 opens, so the lower switch When 9b is repeatedly turned ON and OFF, the electromagnetic relay MC2 is in the excited state. The demagnetization state is repeated, and the contact mc2-2 is repeatedly turned on and off, causing inching. Wear. At this time, the current value flowing through the hoisting motor 4 is a steady value, so Even if the contact mc2-2 is repeatedly turned on and off, there is little wear and tear. In addition, timer T2 will time up following timer T1, so even if one of the timers fails, , it is possible to shift to a state where inching operation is possible.

[0013]

[Effect of the idea]

As specifically explained above in conjunction with the embodiments, according to the present invention, the starting point is a large current. Since inching is not possible while dynamic current is flowing, the life of the current relay is reduced. extends. In addition, when the current reaches a steady state, inching may occur, which may impair work efficiency. There isn't.

[Brief explanation of drawings]

FIG. 1 is a sequence circuit diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an electric hoist.

[Explanation of symbols]

1 Electric hoist 4 Hoisting motor 9 Operation push button 9a Up switch 9b Down switch 10 Three-phase power supply 11 Hoisting brake MC1, MC2 electromagnetic relay mc1-2, mc2-2 contacts T1, T2 timer t1-1, t1-2, t2-1, t2-2 Contact

Claims (1)

[Scope of utility model registration request] [Claim 1] When the switch is turned on, an electromagnetic relay for driving the motor is energized and its contact is closed, and current is supplied to the hoisting motor through the closed contact to drive the hoisting motor. In the control circuit of an electric hoist, once the switch is turned on,
The electromagnetic relay for driving the motor is kept in an excited state for a certain period of time regardless of whether it is in the open state, and after a certain period of time, the electromagnetic relay for driving the motor is energized or turned on depending on whether the switch is turned on or off.
A control circuit for an electromagnetic hoist, comprising a relay circuit that allows demagnetization.