A kind of three-phase solid-state relay protector
Technical field
The utility model relates to a kind of protector, is specifically related to a kind of three-phase solid-state relay protector.
Background technology
At present; The three-phase solid-state relay because contactless, control is convenient etc., and advantage is widely used in industrial control field, but because the three-phase solid-state relay adopts the running of controllable silicon as switch control motor, when controllable silicon partly punctures or during short circuit; The situation of motor will appear burning; Particularly during the motor phase-deficient operation, will be bigger to the threat of motor, in the prior art three-phase solid-state relay circuit is seldom taked safeguard measure; Therefore when the three-phase solid-state relay went wrong, in time handling failure can cause serious economy loss.
The utility model content
The purpose of the utility model provides a kind ofly can protect motor and three-phase solid-state relay, the solid-state protector of the three-phase that motor is not burnt out when the controllable silicon in the three-phase solid-state relay circuit is short-circuited or opens circuit.
For achieving the above object, the utility model adopts following technical proposals:
A kind of three-phase solid-state relay protector; Comprise neutral point testing circuit, protective circuit; The input of said neutral point testing circuit is used to connect the output of three-phase solid-state relay control loop; The output of neutral testing circuit connects the input of protective circuit, and the output of protective circuit is used to connect the signal input end of three-phase solid-state relay.
Said neutral point testing circuit comprises first resistance, second resistance, the 3rd resistance, the 4th resistance and optocoupler; The anode of light-emitting diode connects the three-phase output end of three-phase solid-state relay control loop respectively in the said optocoupler through first resistance, second resistance, the 3rd resistance, and the negative electrode of light-emitting diode connects zero-power line through the 4th resistance in the said optocoupler; Said protective circuit comprises first loop and second loop; Said first loop comprises the 5th resistance and thyristor; The collector electrode of the triode of optocoupler is used to connect the signal input end of three-phase solid-state relay in the said neutral point testing circuit through the 5th resistance; The emitter of triode connects the control utmost point of thyristor, the minus earth of said thyristor, and anode is used to connect the signal input end of three-phase solid-state relay; Said second loop is connected in parallel on the two ends in first loop, and second loop comprises the 6th resistance, the 7th resistance and first capacitor, and said the 6th resistance connects the positive pole of first capacitor and an end of the 7th resistor, the minus earth of said first capacitor respectively.
Also comprise failure indicating circuit, said failure indicating circuit comprises first light-emitting diode, and the negative electrode of said first light-emitting diode connects the anode of thyristor, and negative electrode connects the collector electrode of triode in the optocoupler through the 8th resistance.
Adopt above technological means, the utility model can reach following technique effect:
Because the utility model is provided with the neutral point testing circuit; Voltage that can the detection at any time neutral point, whether the reaction circuit is normal, is provided with protective circuit simultaneously; When being short-circuited as the thyristor of switch in the three-phase solid-state relay circuit or opening circuit; Protective circuit can be cut off the electricity supply, and makes the three-phase solid-state relay avoid being destroyed, and guarantees the safety of motor.
Description of drawings
Fig. 1 is the circuit theory diagrams of the utility model.
Embodiment
As shown in Figure 1: the utility model comprises neutral point testing circuit, first loop, second loop and failure indicating circuit; The input of said neutral point testing circuit is used to connect the output of three-phase solid-state relay control loop; The neutral output that detects connects the input in first loop and the input in second loop respectively; The output in the output in first loop, second loop is used to connect the signal input end of three-phase solid-state relay, and said failure indicating circuit is connected in parallel on the two ends in first loop.
Said neutral point testing circuit comprises first resistance R 1, second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4 and optocoupler U1; The anode of the light-emitting diode among the said optocoupler U1 is used to connect the three-phase output end of three-phase solid-state relay control loop respectively through first resistance R 1, second resistance R 2, the 3rd resistance R 3, negative electrode connects the zero line of power supplys through the 4th resistance R 4; Said first loop comprises the 5th resistance R 5, thyristor VS; The collector electrode of the triode of optocoupler U1 is used to connect first signal input end of three-phase solid-state relay in the said neutral point testing circuit through the 5th resistance R 5; Emitter connects the control utmost point of thyristor VS; The minus earth of said thyristor VS, anode are used to connect second signal input end of three-phase solid-state relay; Said second loop comprises the 6th circuit R6, the 7th resistance R 7, the first capacitor C1; One end of said the 6th resistance R 6 connects first signal input end of three-phase solid-state relay; The other end of the 6th resistance R 6 connects second control signal of three-phase solid-state relay through the 7th resistance R 7; Simultaneously also through the first capacitor C1 ground connection; Said failure indicating circuit comprises the first light-emitting diode DW1, and the anode of the said first light-emitting diode DW1 is through the collector electrode of triode among the 8th resistance R 8 connection optocoupler U1, and negative electrode connects the anode of thyristor VS.
The utility model is provided with the neutral point testing circuit; When the three-phase solid-state relay went wrong, the current potential of the neutral point that first resistance R 1, second resistance R 2, the 3rd resistance R 3 are formed can be very high, optocoupler U1 conducting; When the control loop of three-phase solid-state relay sends control signal; Described signal voltage is provided with the first capacitor C1 through the signal input end of protective circuit connection three-phase solid-state relay in the described protective circuit, the described first capacitor C1 plays time-lag action; Can make voltage signal arrive the time of the time of optocoupler U1 faster than controllable silicon VS major loop in the arrival protective circuit; Therefore can detect whether to exist in the three-phase solid-state relay and puncture the silicon controlled fault: when only puncturing, when voltage signal also is not added to the controllable silicon VS anode in the protective circuit, add conducting voltage between the control utmost point target of controllable silicon VS as the controllable silicon appearance of switch is single; When anode voltage rises to the controllable silicon conducting that can control as switch; The voltage of control signal will all be added on the 6th resistance R 6 and the 7th resistance R 7, be added in this moment on the three-phase solid-state relay control voltage be zero, the three-phase solid-state relay just can conducting; Therefore, can prevent effectively that the three-phase solid-state relay from continuing conducting and damage.When occurring opening circuit as certain controllable silicon of switch in the three-phase solid-state relay, after control signal is added to above the three-phase solid-state relay, as long as two controllable silicon conductings as switch are arranged above the three-phase solid-state relay; The voltage that will make neutral point is 180V, and optocoupler U1 will conducting, controllable silicon VS conducting; The control signal of input three-phase solid-state relay control signal end is zero; The three-phase solid-state relay is in cut-off state at this moment, so motor can phase-deficient operation, has protected the safety of motor.In addition, when controllable silicon VS conducting, the first light-emitting diode DW1 will be luminous, and promptly the first light-emitting diode DW1 will be luminous when the thyristor as switch breaks down, and indicating circuit breaks down.
The utility model is provided with neutral point testing circuit and protective circuit; Said neutral point testing circuit adopts resistance and optocoupler, and protective circuit adopts common electric elements such as resistance, thyristor, and circuit is simple; Guarantee that three-phase solid-state relay circuit makes motor avoid meeting with and destroys when breaking down; The first light-emitting diode DW1 is luminous in the simultaneous faults indicating circuit, indicates circuit and fault occurred, sends fault information to staff intuitively; The staff is handling failure timely and effectively, guarantees the safety of motor.