DE3425792A1 - Electronic protection circuit for machines and electric motors having a constant current consumption - Google Patents

Abstract

An electronic protection circuit for machines and electric motors having a constant current consumption. This protection circuit originates from the field of electronic digital technology. This protection circuit allows machines or electric motors, or both at the same time, to be protected against destruction and overloading. This is achieved purely electronically, by monitoring the motor rated current, rather than via pressure sensors or the like. For example, a pump can be protected against destruction resulting from dry running. The protection circuit can be used for large and small pumps, high-pressure pumps and fan systems. In the case of a large pump, said pump is generally protected via a plurality of pressure sensors. In addition, motor protection is provided by overcurrent protection switches. The circuit which I have developed has the advantage that both machine parts are monitored and protected simultaneously. In the case of a pump system, if, for any reason, the water pressure head is depleted (dry running), the motor is switched off within the set time of 1-10 seconds, via the reduced motor current. The same applies in the case of a blocked pump wheel, where the motor current is greater than the rated current. Switching off likewise occurs in the case of the shaft or coupling breaking down, where switching off occurs on the basis of the idle current. The limits for switching off can be set in wide ranges, using regulators. <IMAGE>

Description

DESCRIPTION Electronic protection circuit for machines and electric motors with constant Strumau + take! To the best of my knowledge, machines such as pumps or Fan with pressure fuel or other mechanical devices monitored. Electric motors on the other hand only with overcurrent circuit breakers.

The task is to use machines or electric motors or both at the same time a device to monitor.Here it is important not only to "over" the current (Machine blocked), but also the current should "under" (machine does not work normal) and the "no-load current" (motor separated from the machine due to a defect) capture.

The circuit works as follows: Prerequisite, P1 at the stop maximum, P @ at stop minimum. After applying the supply voltage, LED-A lights up = Shutdown. When the ET button is pressed, the relay and the auxiliary contact "H" are activated. LED "B" operation lights up.

The self-holding is generated by IC 4093, which is now at the points 5-6 0 Signalqan 8-9 via 1M and switch above IC 4066 L signal at points 4 and 11 IC 4093 also L signal and the BC107 switches through @ -U converter is switched into a 5A motor current converter circuit. The machine switched on, a voltage builds up at point M, which is set to about 10V with P5 The higher starting current is set with P4, switch-off time "over", setting approx. 1-10 sec. bridged.

At IC 4093 point 5 there is now 12V, at point 6 approx. SV is set with P3, see above remains at point 4 L signal. At point 1-2 of IC 4093 and point 5 of IC 4066 lies also 12V. At point 3 of IC 4093 there is o signal. Switch on top IC 4066 is open, switch at the bottom is closed. With P1, about 7V is set at IC 4093 point 9 Point 8-9 IC 4093 is L signal and therefore also at point 11. The auxiliary contactor remains attracted and the machine runs.

If the machine blocks, the motor current increases and with it the voltage, after the set time, at point 6 of IC 4093 to over 7V. IC 4093 switches on Now at point 4 from L to 0 signal The BC107 and the relay including the auxiliary contact fall from, (shutdown "over" should). If the power consumption of the machine falls below normal, + aellt the voltage at point 9 IC 4093 is below 6V. At point 10 IC 4093 is then L signal and at point 11 0 signal. Relays and auxiliary contactors drop out again, (shutdown "below" If the engine is idling (without machine), IC 4 is at point 9 (193 L signal.Now is set with P6 at point 5 IC 4066 5V, the switch at the bottom must close so that Deactivate relays and contactors With this Switching, additional monitoring can also be implemented further LEDs can be used to indicate what type of shutdown is or was.

This protective circuit can be electric motors and machines or both at the same time It can be used for small, large or high pressure pumps and fans systems etc. This means that the individual monitoring of Motors and machines connected to them.

This circuit can be used in industry, mining, trade, agriculture and the water supply.

It can be produced inexpensively and replaces the usually expensive ones «Or additional mechanical monitoring devices of previous design.

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Claims (1)

P A T E N T A N S P R U E C H E F U E R: Electronic protection circuit for machines and electric motors with constant power consumption! characterized in that Machines such as pumps or electric motors or both can be protected at the same time The most important feature here is that the machines are switched off below the rated current or with no-load current Protective circuit remains on "Evetr-ieb"