JPS58207297A - Preventive device for overload of electric winch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention relates to the current of a hoisting induction motor and 'N, tA'! l
For example, if the input power calculated from pressure and t exceeds a set value, the operation of the electric motor is stopped! This invention relates to an improvement in an overload prevention device for a winding machine such as a wind hoist.

The conventional device of this type has the drawback that it cannot accurately prevent overloading because the set value is constant regardless of changes in the power supply voltage.

This invention has been made to solve the above-mentioned deficiencies in the conventional art, and will be described below with reference to FIGS. 1 to 8 as one embodiment of the invention. In the figure, r, s, t
is a three-phase AC power supply, a power supply cable connected to each phase of R, 8, and T, and M is a three-phase father winding connected to the power supply cable (r, s, t) via a reversible electromagnetic contactor, which will be described later. Doyo induction motor, CU is a magnetic contactor that is energized during hoisting operation of Z-motor #1M, and OUa+, CUai,
It has a normally open main contact of 0Uaa, a normally closed auxiliary contact of OUb, and a coil OUc. CD is an electromagnetic contactor that is energized during lowering operation of motive M, CDa+,
CDa2. CDam) has a normally open main contact, a normally closed auxiliary contact CDb, and a coil CDc.

TR+ and TRg are transformers constituting a means for detecting power supply voltage (voltage), OT is a current detector (current detector) for detecting the W-phase current of motor M, and CC is a single transformer as detailed in Fig. 2. '(Press force and current detection Hy c ') from TRg
Detect power from current input and t (force detector 8p and input 1 to the motor at rated voltage and rated hoisting load; input to set squid 11Ik as reference value)
As shown in Fig. 8, the electric power standard value setter SSp and the correction coefficient for selecting a correction coefficient that changes at the same rate of change as the change in source voltage. The selector 8 has a multiplier Ck which multiplies the set value of the force reference value setter by the correction coefficient selected by the correction coefficient selector 8 and outputs an output corresponding to the correction value vf. This control circuit is constructed on a board and includes a comparator H that compares the output of the detector 8p and the output of the JE device ck.

Ry is a relay that is energized by the output of the comparison i:iK when the output of the power detector 8p exceeds the output of the multiplier Ok, and has a normally closed contact Ryb. Bu is a normally open push button switch for hoisting operation, and Bd is a normally open push button switch for lowering operation.

Like this? - in the configuration, switch B
When u is turned on, CUo is energized and contacts CUa+, CU
Since ax and 0Uas are closed, the electric motor #MM performs hoisting operation, and when the switch Bu is turned off, the hoisting operation is energized and contacts CDa+, CDax, and CDam are closed. It's moving! ll! Δ1 performs the lowering operation, and when the switch Bd is turned off, the lowering operation is stopped and the lowering operation is started. Further, if an overload operation is to occur during the hoisting operation, the relay Ry is energized, the landing gate yb is opened, and the hoisting operation is carried out. Also, when the source pressure changes during operation, the output of the force detector Sp also changes, and the output of the multiplier Ck also changes accordingly, so the relay y is activated. Tokihiro's '(Motive M's load condition!Imagination is always constant and overload operation is prevented.

Since the present invention is constructed as described above, it is possible to not only prevent overload operation of the moving hoisting machine, but also to control the load condition in relation to changes in the vertical Δq mountain pressure. I am extremely proud of the fact that I can always maintain a constant and accurate load condition without using the machine.
□It is effective.

[Brief explanation of drawings]

The figures are of the -'14 example of the present invention, in which figure @1 is an operating circuit diagram, figure 2 is a detailed diagram of the control circuit, and figure 3 is a squareness coefficient diagram. In the figure, M is for "winding up" (seeing movement).
CN6 hoisting 4 conversion '4L Wi connection 1'lfl device,
TR+, , TfLz i? , 'r13: L detection means (transformer), CT is the current detector, CC is the control circuit, 8p is the force output 3, Ssp is the input squid reference value setting word, Sk is the correction coefficient selector, Ok is the In the figure, the same reference numerals are the same or indicate the first part. Deputy Enter Ge Shu Shin - Figure 2

Claims (1)

[Claims] Means for detecting the source voltage and current of the hoisting induction ltMI71 machine, means for determining input power from the above voltage and current, and hoisting operation of the above motor when the value of the above input power exceeds a set value. An overload prevention device for an electric hoist, characterized in that the overload prevention device is provided with a means for stopping the nucleation.