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Phase Failure Three Phase Voltage Relay Overvoltage CE / CCC Certification
Phase sequence protector principle
Phase Sequence Protector Principle Under normal circumstances, the
wiring order of the motor work is regulated. If for some reason,
the phase sequence is disordered, the motor will not work properly
or even be damaged. Phase sequence protection is to prevent such
accidents from happening.
Phase sequence protection can use phase sequence When the phase
sequence in the circuit does not match the specified phase
sequence, the phase sequence relay will trigger the action and cut
off the control circuit so as to cut off the motor power supply and
protect the motor.
Three-phase alternating current phase sequence detection circuit is
composed of helium bubble NB. Due to the phase-shifting effect of
C1, when the power supply is connected in the phase sequence of A,
B, and C in the figure, the helium bubbles emit light, and when the
reverse phase sequence is connected to A, C, and B, the helium
bubbles are not bright.
When the start button QA is pressed, the alternating current is depressurized by C2, VD1, and rectified and DW to obtain a DC voltage of 12V, which is added to the protection execution circuit composed of the relay K and the photosensitive resistor tube V. If the order of the phases is A, B, and C, then the helium bubbles emit light, and the CDS packaged with the helium bubbles exhibits a very low impedance after being irradiated with light, and then V gets a biased base current and conducts. K picks up, K1 Connect the AC control circuit, C pulls in and the motor starts running. On the other hand, if the reverse phase sequence is followed, the bubble does not light, K does not pull, and K1 turns off, and the motor cannot be started. This achieves the purpose of protection.
Features
Phase sequence protection device can be divided into two types:
contact phase sequence protector and non-contact phase sequence
protector. The former uses electromagnetic relays or AC contactors
as its actuators, while the latter uses solid-state relays
(thyristors, IGBTs, high-voltage VMOS transistors) as its
actuators. The former uses the contacts of an electromagnetic relay
or AC contactor to break the phase-sequence faulty three-phase
power supply, while the latter uses an electronic component to turn
off the faulty power supply. Therefore, compared with the former,
the latter has the characteristics of fast response, no noise, no
spark, long life, small size, and high mechanical strength. The
former is relatively the latter, has a high breakdown pressure,
withstand overload, low cost, etc. Features.
Three-phase monitoring of phase sequence, phase loss, over- and undervoltage and phase unbalance
♦ Technical data
Type | JVR-380W |
Measuring circuit | L1.L2,L3 |
Rated Voltage | 220VAC,380VAC,440VAC,460VAC,480VAC,50/60Hz |
Monitoring functions | phase sequence,phase loss,overvoltage,undervoltage,phase unbalance |
Voltage setting range | ±5%~±20% |
Indicators | phase sequence,phase loss,overvoltage,undervoltage,and normal |
Output contacts | 1 C/O |
Contact capacity | 3A,250VAC |
Dimensions(H x W x D) | 68*30*76 |
Mounting | DIN rail |
Weight | 0.2kg |