Todays deals on Current Relay?

Schweitzer Eng SEL-311L Line Current Differential Relay $4,750.00

ABB / Westinghouse Type SC Instantaneous Adjustable Current Relay 1878397 $3,500.00

SEL-387E Current Differential and Voltage Relay $2,500.00

Allen-Bradley INSTANTANEOUS TRIP CURRENT RELAY 600VAC/VDC 87A 809-A15E Series A $1,657.50

GE ground directional over current relay model # 12JBCG53M8Y1A $1,500.00

SEL-387 Current Differential & Overcurrent Relay 110VDC $1,440.00

A-B 809S-NX1 AC CURRENT JAM RELAY 120V 7.5A T=.42-5A AC $1,199.00

NEW ALLEN BRADLEY 810-A08B INVERSE TIME CURRENT RELAY $1,179.99

Square D DashPot Magnetic Current Relay # 9055A0124R $1,100.00

A-B 809S-AB100A1 AC CURRENT RELAY 120V 7.5A T=.42-5A AC $999.00

ALLEN-BRADLEY 809-A03E INSTANTANEOUS TRIP CURRENT RELAY 4.0 AMP CONTINUOUS NEW! $944.99

Allen Bradley 809-A03E RELAY CURRENT INSTANTANEOUS TRIP $974.99

ALLEN BRADLEY RELAY CURRENT INSTANT TRIP 809-A03E 2330 $959.99

*NIB* Allen Bradley 809-A03E Instantaneous Trip Current Relay 809A03E Controller $899.99

ALLEN BRADLEY INSTANTANEOUS TRIP CURRENT RELAY OPEN 12AMP 600V 809-A06E 809A06E $850.00

ALLEN BRADLEY INSTANTANEOUS TRIP CURRENT RELAY OPEN 4AMP 600V 809-A03E 809A03E $850.00

New Allen-Bradley 809-A05E Instant Trip Current Relay $850.00

NIB ALLEN-BRADLEY, CAT.NO. 809-A12E, INSTANTANEOUS TRIP CURRENT RELAY (BIN 43) $750.00

NIB ALLEN-BRADLEY, CAT NO. 809-AO3E, INSTANTANEOUS TRIP CURRENT RELAY (BIN 43) $750.00

ALLEN BRADLEY 809-A07E NEW TRIP CURRENT RELAY 809A07E $750.00

Allen Bradley Inverse Time Current Relay 12 AC/DC Amps Continuous 810-A06A NIB $719.99

ELECTROMATIC SJ125 120 DC CURRENT LEVEL RELAY 0.1-20mA $699.00

Allen Bradley 810 Inverse Time Current Relay 810-A08A $679.99

Allen Bradley 809S-AB100A1 AC Current Relay $650.00

ALLEN BRADLEY 809-A03E INSTAN. TRIP CURRENT RELAY $649.99

CUTLER HAMMER IQ 500 IQ502A 9966D61G01 CURRENT SENSING QUANTITY!!! $550.00

Allen Bradley 809S Solid State AC Current Relay 809S-AB100A1 $625.00

ABB LCB8T1T5NN LCB II Current Differential Relay Switch $622.00

NEW SEALED RELIANCE ELECTRIC 64418-600D CURRENT SENSING RELAY 64418600D $600.00

ALLEN BRADLEY RELAY CURRENT INSTANT TRIP 809-A02E 2331 $599.99

NIB ALLEN-BRADLEY,CAT.NO. 809-AO4E, INSTANTANEOUS TRIP CURRENT RELAY, (BIN 43) $550.00

ABB OVER CURRENT RELAY STYLE 264C901A07 TYPE C09HIL0 NEW IN BOX UNOPENED $499.99

505-5518 High Current Relay Module $475.00

LOT OF 4 PHOENIX CURRENT MONITOR VOLTAGE RELAY EMD-FL-C-10 USED $475.00

ABB LCBII CURRENT DIFFERENTIAL RELAY SWITCH LCB8T1T5NN $426.55

WESTINGHOUSE / ABB 292B400A14 INSTANTANEOUS ADJUSTABLE CURRENT RELAY TYPE SC 10- $450.00

CUTLER-HAMMER D60LA1 ADJUSTABLE AC CURRENT RELAY $399.99

Allen Bradley 810 Inverse Time Current Relay 810-A09A $424.99

GENERAL ELECTRIC PCJ-32D78A INSTANTANIOUS OVER CURRENT RELAY NIB $399.99

EATON Cutler-Hammer D60LA0 Adjustable Current Relay $399.99

ALLEN-BRADLEY CURRENT OVERLOAD MONITOR RELAY 193-EC3ZZ $400.00

ABB T+D COMPANY WESTINGHOUSE 292B400R14 SC CURRENT RELAY NEW $409.00

NIB SQUARE D Dashpot Type Magnetic Current Relay 9055 AO 123R $375.00

K-Tec Littelfuse RCD300M2 Differential Current Relay $347.50

AB ALLEN BRADLEY 809-A01E 2 AMP INSTANTANEOUS TRIP CURRENT RELAY AC DC 600 VOLT $350.00

New – Allen Bradley 809-A05E Instantaneous Trip Current Relay $339.00

NEW Allen Bradley Instantaneous Current Relay 809-A23E $348.49

Eaton Cutler Hammer Current Sensitive Relay and Transformer D60LA D60LT6 NIB $339.99

Allen Bradley Relay 193-B1N6 A Current Range 96-300A Current Ratio 300/5 $308.75

Square D DashPot Magnetic Current Relay # 9055A0-121R $275.00

NEW! Ktec Leakage Current Sensing Relay RCD 300M2 $300.00

NIB ABB SC CURRENT RELAY 292B400A15 $289.00

NEW ABB 292B400A12 TYPE SC CURRENT RELAY 2-8 AMPS $289.99

OFFER & WIN – Allen-Bradley 193-EC1AB Current Range 1-5A Relay $220.00

ALLEN BRADLEY 193-EA1KE OVERLOAD RELAY CLASS 10 CURRENT RANGE 26-85A SER A NIB $269.99

Cutler-Hammer D60LA0 Adj. Current Relay *NEW* $250.00

BASLER ELECTRIC NIB BE4-37/51 CURRENT RELAY (ES15) $265.00

ELECTROMATIC SJ105 724 S SYS 1-5ADC CURRENT LEVEL RELAY $249.90

ELECTROMATIC SM215 120 S SYS CURRENT LEVEL RELAY 0-10 $249.90

ELECTROMATIC SJ105 115 S SYS 1-5ADC CURRENT LEVEL RELAY $249.90

New Furnas/Siemens 97AMF0416 Current Relay $249.99

Allen Bradley Current relay $205.00

Culter Hammer Current Relay D60LA0 NEW $250.00

NIB TELEMECANIQUE RM3JA102FG7 CURRENT MEASUREMENT RELAY RM3 JA102FG7 $250.00

NEW SQUARE D 9055AO121R MAGNETIC CURRENT RELAY $225.00

MOORE INDUSTRIES DDA/4-20MA/DH1L1/24DC-AD DC CURRENT ALARM RELAY ***XLNT*** $229.00

Square D Relay Magnetic Current 9055-AO121R (3917) B $224.99

1 FURNAS 97AMF0416 CURRENT SENSITIVE RELAY Q5-4 $225.00

CROMPTON 252-PAO4-000422 OVER CURRENT RELAY w. DELAY QUANTITY!!! $199.99

FURNAS 97AMF0207 CURRENT SENSITIVE RELAY NIB!!! $225.00

ALLEN BRADLEY 809S-AB010A1 AC CURRENT RELAY *NEW* $225.00

NEW ALLEN-BRADLEY 809-A01E INSTANTANEOUS TRIP CURRENT RELAY $210.00

FURNAS 97AMF0207 CURRENT SENSITIVE RELAY NNB!!! $215.00

Allen Bradley Inverse Time Current Relay 810-A09C NR $220.99

NEW IN BOX FURNAS CURRENT SENSITIVE RELAY 97AMF0207 $210.00

WESTINGHOUSE CO-9 STYLE 264C901A01 OVER CURRENT RELAY NEW IN BOX $199.99

CRESTRON ST-CS(ZA103420) DUAL CURRENT SENSOR 90-125VAC $199.90

SQUARE D TR1.4 OVERLOAD RELAY W 3PHASE CURRENT SENSOR $199.00

SQ D DASHPOT MAGNETIC CURRENT RELAY CL 9055/B0-117R $202.00

ABB Residual Current Device S261UCC40 NIB ! $214.00

Allen Bradley AB 809 Instant trip current relay $199.99

CARLO GAVAZZI SJ155 115 CURRENT LEVEL RELAY 1-5A SPDT $199.90

ELECTROMATIC SJ175 115 CURRENT LEVEL RELAY 0.2–1A REFU $199.90

NIB SQUARE D DASHPOT MAGNETIC CURRENT RELAY OPEN TYPE AUTO RESET, (BIN 43) $200.00

ELECTROMATIC SXS128 724 S SYSTEM 128 CURRENT SUPPLY NEW $199.90

CARLO GAVAZZI SJ155 024 CURRENT LEVEL RELAY 100-500mA $199.90

Westinghouse C09-C411BA1 Style 1875288 Relay Over Current New $175.00

RED LION 33160 Batch Counter with Relay & Current Loop $200.00

CARLO GAVAZZI SJ175 115 CURRENT LEVEL RELAY 0.2–1A NEW $179.90

D60LT5 CUTLER HAMMER RELAY CURRENT SENSITVE TRANSFORMER $189.00

Brand New! ABB Over or Under Current Monitoring Relay $178.00

Allen Bradley 600V Inverse Time Current Relay 810-A11C $178.49

CARLO GAVAZZI SJ175 115 CURRENT LEVEL RELAY 0.2–1A REF $159.90

Eaton Cutler Hammer Current Sensitive Relay and Transformer D60LA D60LT6 $169.99

NV-Z40A Mitsubishi New In Box Earth Leakage Relay Current Transformer NVZ40A $159.99

CR MAG CR4395-EL-120-330-A-NC/ELR CURRENT SENSOR RELAY $149.00

CARLO GAVAZZI DIB01C7245A CURRENT RELAY 24VDC SPDT 8A $149.00

Cutler Hammer AC Current Transformer D60LT2 NEW $160.00

NICE NORDIC CURRENT SENSITIVE RELAY MODEL 3113A13 $149.00

CARLO GAVAZZI EID C115 20mA CURRENT LEVEL RELAY 115VAC $149.00

Current Relay Questions

A.C. Solid state relay circuit and structure

Solid state a.c. relays are well known. Such relays, with optical isolation between input and output, are also well known. In presently existing devices, many discrete components are commonly required to complete the a.c. circuit. Thus, it maytake thirty or more discrete thyristors, transistors, resistors and capacitors to manufacture a single device. Attempts have been made to integrate the various parts of the entire solid state relay, but these have met only limited success due to the mixof high voltage and high power components.

Solid state relays made in the past have also employed zero voltage crossing circuits to ensure turn on of the thyristor only when the a.c. voltage is within some small “window”. These circuits have also been relatively complex and difficult tointegrate into the main power chip. Thus, zero cross firing circuits have required the use of a discrete resistor connected across the power terminals. These resistors have not been easily integrated into a single chip because of the difficulty offorming this resistor on the chip surface.

It has also been difficult to provide so-called “snubberless” operation for the relay under any inductive or resistive load. Thus, while solid state relays may operate well under resistive or slightly inductive loads, they may tend to “halfwave” or “chatter”, which is a condition wherein a relay turns on only for one-half of a cycle, under a highly inductive load. This has occurred in the past because the relays are commonly provided with conditioning circuits for suppressing fast turn onof the circuit under some fast transient or high dV/dt condition. When the device is operated under a very highly inductive load, however, voltage transients are commonly generated repetitively during device turn on. When the signal conditioningcircuit misinterprets this as a transient signal, it shuts off the power output during a particular half phase of the operation. The circuit will then appear to turn to normal during the next half wave and the relay will turn on. This condition repeatsso that the relay turns on only during one or another of the half waves of the full cycle. To avoid this condition, relays of the past have been formed with reduced firing sensitivity and this has required reduction of sensitivity to optical firing.

Since prior art relays have been relatively complex, they have required substantial volume for their housings. Moreover, solid state relay of the past have been limited to a maximum temperature rise of about 110° C., thus limiting theircurrent-handling capability. Finally, solid state relays of the past have been relatively expensive in view of the need for large numbers of discrete components and large housings.

In accordance with the present invention, two identical thyristor power chips are provided for an a.c. relay wherein the power chips are both of lateral construction with both cathode and anode electrodes at one surface of each device and whereineach of the chips can be optically fired and has an optically sensitive upper surface which, when illuminated, will permit the device to become conductive between its anode and cathode electrodes.

The gate circuit of each of the thyristors is connected to a novel control circuit, formed either of discrete components or of components merged within the body of the semiconductor material forming the thyristor. The control circuit is operableto prevent turn on, even though the surface is illuminated, when the voltage across the device exceeds a value greater than some predetermined window value, or when high dV/dt transients appear across the device. This control circuit includes a clampingtransistor which can be turned on to clamp the gate of its respective thyristor and a capacitive divider circuit connected across the main power electrodes. The capacitive divider applies a control signal to the control transistor.

One of the capacitors of the capacitive divider includes the distributed capacitance of the control transistor. So long as the control transistor is on, its respective power thyristor cannot turn on even though its surface is illuminated. Thecapacitive divider is arranged so that the control transistor is normally turned on for all absolute voltages across the main device greater than some relatively small window value. Thus, the power thyristor cannot turn on outside of this small windowvalue or zero cross value.

The novel capacitance divider, in combination with the control transistor, will now operate to suppress both fast transients and still allow the device to function under its normal load condition. Thus, voltage transients which are generatedrepetitively during device turn on under highly inductive load conditions will not be misinterpreted as a fast transient and the power thyristor chip will be permitted to turn on in its normal manner under even highly inductive loads.

The novel signal conditioner of the invention also allows for substantial improvement in optical sensitivity of the device without misfiring. Note that currently available optically isolated triac drivers and the like are always limited eitherin dV/dt capability or optical sensitivity because of their inability to separate low level command signals from transients.

A novel housing is provided for the two chip arrangement in which the two chips are easily and inexpensively connected in parallel with one another and are protected from the outer environment. An alumina substrate or other suitable heatconductive but electrically insulative substrate is provided with suitable conductive patterns thereon for receiving the various chips of the switch and for connecting the chip electrodes to suitable output leads. The two identical thyristor chips whichare to be connected in anti-parallel are symmetrically secured to respective conductive pads on the substrate and are in alignment with one another and with the terminal ends of two conductive patterns on the substrate. Two continuous wires are thenstitch-bonded to the thyristor pads and conductive leads in such a manner that one lead wire is electrically connected to the anode pad of one chip, the cathode pad of the second chip and one of the conductive patterns which is connected to an input a.c.lead. The other wire is similarly connected to the other electrodes and conductive pattern to conduct the thyristors in anti-parallel.

plastic cap of a white illumination reflecting material then is secured to the substrate and covers the region of the substrate containing the LED and the two power chips. The interior of this cap may be filled with a transparent plastic whichencloses and encapsulates the surfaces of the chips and their interconnecting leads.

If the control circuit for the power transistor is carried out in discrete form, the discrete components may also be suitably connected to this substrate. Preferably, however, these components are integrated into the individual power chips sothat the entire solid state relay will consist of two power chips and their controls, the LED chip and the various support structures previously described.

About the Author

Greegoo is a ISO9001 certified professional manufacturer and exporter of thyristor diode modules, solid state relay, phase control thyristors, rectifier diodes, circuit breakers, switching power supply, magnetic and dc contactors, proximity and photoelectric sensors, safety light curtains, limited switches, digital panel meters, current transformers and switchgears etc.

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