CN2036324U

CN2036324U - Metallic thermal resistance type over load and heat protector for electric motor

Info

Publication number: CN2036324U
Application number: CN 88202589
Authority: CN
Inventors: 郭永明
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-03-26
Filing date: 1988-03-26
Publication date: 1989-04-19

Abstract

The utility model discloses an over load and (or) over heat protector for electric motor (comprising domestic freezer compressors). The utility model is characterized in that a metal fever resistor is adopted as the detecting element of the electric current and temperature rising changes. The over load and (or) over heat protector for electric motor (comprising domestic freezer compressors) can simulate the over load (overflowing) conditions of the electric motor. Domestic consumers can use the protector for rapidly validating whether an apparatus is misadjusted or ineffective so that failure can be prevented from being continuously used. An apparatus can not be misadjusted or ineffective by being affected by the factors of passing through a short circuit current, a mounting position, an environment temperature, etc. The conditions that the electric motor can be damaged by the over load and over heat which are caused by lacking phases, large voltage fluctuation, instant power outage, lacking lubricating-oil and not good heat radiation can be effectively prevented from being generated. The utility model can also be used for protecting a power generation (transfusion) equipment from being over load, over heat and (or) over current.

Description

Metallic thermal resistance type over load and heat protector for electric motor

The invention relates to motor (comprise domestic refrigerator compressor, down with) overload and (or) overtemperature protection system, particularly with metal fever resistance be detecting element electromotor overload with (or) overtemperature protection system.Motor take place often because of phase shortage, voltage fluctuation are big, instantaneous power failure, heat radiation are bad, lack lubricating oil, etc. former thereby overload, the overheated situation that motor is damaged.Motor bimetallic type thermal relay commonly used is made overload protection.Its advantage is simple in structure, easy to use, just often can carry out overload protection effectively.But Chang Yin by short circuit current, actuating mechanism block, corrosion, installation site are unreasonable etc., and reason lost efficacy the thermal relay imbalance, i.e. action is too slow or be failure to actuate; And thermal relay adjustment requirement is high, trouble is time-consuming.Unconditional verification of some users or irregularly verification, the relay that making lacks of proper care lost efficacy still uses for a long time, damages when causing motor overload.In addition, because thermal relay does not have overheat protective function, can not prevent that motor from taking place because of overheated and impaired situation.Motor protection against overheat bimetallic type temperature relay commonly used and thermistor protective circuit.The former to imbed electronic in, long, action resetting time lags behind; Latter's complex circuit, selling at exorbitant prices, technology inconvenience.Can be simultaneously motor be transshipped the double-metal sheet type relay of overtemperature protection.As: be used for the heat protection starting relay of freezer compressor protection abroad, existence can not be regulated, and is difficult to promote in maintenance.

First purpose of the present invention provide a kind of can to motor transship and (or) overtemperature protection, and the protective device that can regulate.The overload current of protective device action, the setting value of overtemperature and overload or overheated duration respectively with the motor rated current, allows temperature rise, start-up time linear.

Second purpose of the present invention provide and a kind ofly be not subjected to ambient temperature, mounting condition, by factor affecting such as short circuit current, the corrosion protective device that lost efficacy of imbalance just.

The 3rd purpose of the present invention provides a kind of protective device with simulated machine overload (overcurrent) function, and domestic consumer can be fast, whether convenient checking protective device lacks of proper care inefficacys, the protective device continuation use that prevents to lack of proper care and lost efficacy.

The present invention adopts metal fever resistance as electric current, temperature change detection element, allows current of electric directly by thermal resistance, branch road that LED, diode are arranged in parallel on each thermal resistance, and LED controls an adjustable delay switch circuit; The mode that metal fever resistance is close to the motor temperature high-order bit motor is transshipped and (or) overtemperature protection.

Fig. 1 be single-phase motor or domestic refrigerator overload of compressor and (or) line map of overtemperature protection system.Rt is and motor M power line or windings in series among the figure, the metal fever resistance that motor current directly flows through.One in parallel has LED, the branch road of elements such as diode D on Rt.When the motor operating current increased, the pressure drop on the resistance R t increased; When the rising of M temperature, resistance R t increases, and the last pressure drop of Rt also increases.When M operating current or temperature rise surpassed setting value, the pressure drop on the Rt increased to and makes the LED with stabilized voltage characteristic luminous, with the photoelectric tube BU conducting of LED coupling.Surpass setting value, power supply V when transshipping, cross thermal endurance ₊By BU, adjustable resistance R ₂To the capacitor C charging, C voltage is risen to make triode BG conducting, the relay J action of control power supply, alarm.Otherwise relay just is failure to actuate.When M operating current, temperature rise during all in normal range (NR) the pressure drop on the Rt can not make LED luminous, protective device is failure to actuate.

Fig. 2 be three-phase alternating-current motor overload and (or) the overtemperature protection system line map.

Adopt metal fever resistance formula electromotor overload and (or) overtemperature protection system compared with prior art, can significantly reduce that motor is big because of phase shortage, voltage fluctuation, instantaneous power failure, heat radiation are bad, lack the situation that lubricated wet goods reason causes motor to damage takes place.

This device also can to the generator power transformer do overload and (or) overtemperature protection, high voltage transmission line, enterprise, family are done the overload flow protection.Being used with A.C. contactor, is the best way that realizes electrical appliance is carried out overload protection.

Claims

1, a kind of employing metal fever resistance as electric current and (or) electromotor overload of temperature change detection element and (or) overtemperature protection system; be characterized in branch road that LED is arranged in parallel on the metal fever resistance that motor current directly flows through, LED is with light control switch circuit.

2, one as right 1 described electromotor overload and (or) overtemperature protection system, be characterized in that LED connects with diode.

3, one as the described electromotor overload of right and (or) overtemperature protection system, be characterized in that metal fever resistance and motor temperature high-order bit be close to.

4, one as right 1 described electromotor overload and (or) overtemperature protection system, be characterized in that the switching circuit of LED control is adjustable delay switch circuit.