JPS6116734Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE The present invention relates to an alarm system for a pump control panel to protect a motor pump.

If a foreign object gets caught in the pump while it is operating, or if the pump becomes overloaded due to other reasons, the motor must be stopped to protect the motor. Conventionally, a protection device such as an overload relay was installed in the motor circuit, and when an abnormally large current flows through the motor, this protection device is activated and an alarm system is generally adopted that activates a buzzer or indicator light. There is.

However, focusing on the fact that an overcurrent flows through the motor, for example, when the pump is overloaded due to foreign matter, reverse operation, or open-phase operation due to loose or disconnected connection terminals, if this overcurrent flows, Recently, motors with built-in protection devices that cut off the circuit when the heater generates heat and activate the bimetal have begun to be used to drive pumps. By the way, this protection device inside the motor tends to operate earlier than the protection device in the control panel, that is, the overload relay installed in the motor circuit, so when the protection device inside the motor is activated, the current to the motor is reduced. Since the overload relay is disconnected, the overload relay does not operate, and therefore an external control panel cannot detect abnormalities in the motor or pump. In other words, conventional control panel alarm systems that have protection devices such as overload relays in the motor circuit cannot be applied to motors that have built-in protection devices inside the motor. has the disadvantage that pump abnormalities cannot be detected by an external control panel. It is also possible to take out the signal that activates the alarm directly from the protection device inside the motor, but if such a signal line is provided, the number of codes coming out of the motor will increase unnecessarily, and the control panel will not be able to receive the signal. It cannot be generally adopted because it has drawbacks such as the need for additional terminals.

The present invention aims to provide an alarm system for a pump control panel that does not have the above-mentioned drawbacks. To provide an alarm system for a pump control panel which can warn of abnormalities in a motor or pump on an external control panel even after the motor or pump is activated, and can be applied to motors other than motors having a built-in protection device inside the motor.

The pump control panel alarm system according to the present invention is
An alarm device consisting of an indicator light or a buzzer, an abnormality detection means for detecting an abnormal current of a motor that drives a load, and a signal detected by the detection means and sent to the alarm device. an operating circuit, an undercurrent relay for detecting a state in which no current flows even though the abnormality detection means is applied with voltage, and an overload relay connected in series with the undercurrent relay; Provided in the motor circuit.

Therefore, if an abnormality occurs in the pump, such as foreign matter or wire breakage, the protection device inside the motor will generally operate faster than the overload relay, but at that time, although voltage is applied to the motor, the current Since the current does not flow, the undercurrent relay is activated and sends an alarm signal to the alarm.

Furthermore, in the case of a general motor that does not have a built-in protection device, an overcurrent flows through the motor circuit due to an abnormality in the motor or pump, which activates the overload relay and, as a result, activates the alarm. Therefore, the present invention can be applied to all pump motors, regardless of the presence or absence of a protection device inside the motor, and can detect abnormalities in the pump and motor from the external control panel, allowing the cause of the abnormality or failure to be quickly discovered. can.

Hereinafter, an embodiment of the present invention will be explained in more detail with reference to the drawings. M is a motor that drives a pump P, and electric power is supplied to the motor M by a motor circuit 1. ing. The motor circuit 1 includes a circuit breaker 2 and an electromagnetic switch 3.
are provided in a known manner. An undercurrent relay 4 and an overload relay 5, which are abnormal current detection means, are directly connected to the motor circuit 1. Each of these relays 4 and 5 is connected to an operating circuit 6 and sends its signal to the operating circuit 6. The operating circuit 6 operates an alarm 7, a buzzer, and an indicator light based on signals from the relays 4 and 5. S in the figure is a control panel.

An undercurrent relay is a relay that operates when the current falls below a set value, and when used as a protection device for a motor pump, the set current value can be set to zero and other set values are unnecessary. A liquid level detector 8 comprising a float switch or the like is further connected to the operating circuit. The electromagnetic switch 3 is opened and closed by an electric signal from an operating circuit 6.

During operation, if a motor M with a built-in protection device is used, the pump may be overloaded due to foreign matter such as sand, or run in reverse.
In the case of open phase operation due to loose connection terminals or disconnection, the protection device inside the motor is activated, but when the protection device inside the motor is activated, the motor M
Since the current is not flowing even though voltage is applied to the terminal, the undercurrent relay 4 is activated and the alarm 7 in the control panel S issues an alarm.

Therefore, although the protection device inside the motor is generally activated quickly by the overload relay 5, when the protection device inside the motor is activated, the undercurrent relay 4 is activated, so the abnormality cannot be detected from the external control panel S. can.

If a general motor without a built-in protection device is used, if an abnormality occurs in the motor or pump, an overcurrent will flow through the motor circuit 1, which will activate the overload relay 5 and shut down the operation circuit 6.
The alarm 7 is activated by a signal from the alarm.

As described above, according to the present invention, an undercurrent relay and an overload relay are provided in series in the motor circuit, so it can be applied to all motors regardless of the presence or absence of a protection device inside the motor, and can be applied to all motors such as pumps or motors. Abnormalities can be detected at the control panel, i.e. externally,
Therefore, the effect is that the cause of the abnormality can be quickly removed.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing an embodiment of the present invention. P...Pump, M...Motor, 4...Undercurrent relay, 5...Overload relay, 6...Operation circuit,
7...Alarm.

Claims (1)

[Scope of utility model registration request] An alarm device consisting of an indicator light or a buzzer, an abnormal current detection means for detecting an abnormal current of a motor that drives a load, and a signal detected by the detection means to send an alarm signal to the alarm device. and an overload relay connected in series with the undercurrent relay, which detects a state in which current does not flow even though the abnormal current detection means is applied. , an alarm system for a pump control panel, characterized in that it is provided in a motor circuit.