Latching relay

Thermal Dispersion. Thermal dispersion level switches are used on appHcations where multiple shifts inhquid characteristics are present. The unit is responsive only to a change in the thermal conductivity of the Hquid and ignores shifts in specific gravity, dielectric, density, temperature, and pressure. Units are used for alarm signal however, pump control maybe obtained using two units with a latching relay. 

Control relay Fan motor Gear motor Solenoid valve Rectifier, I20VAC/90VDC Reversing-Drive clutch Reversing-Drive clutch Latching relay Latching relay... 

RLY 1, RLY 2 - Open frame 4 PDT 12 volt DC latching relay, 20 or more amp capacity. 

Fig. 12.6 A latching relay circuit, used as a circuit breaker.

The phrase "positive feedback" means that, when a device like a relay operates, a signal of some sort is sent back to the beginning of its circuit, to continue its operation, or make its operation stronger. Another description of this circuit is "latching relay," although that can also mean a strictly mechanical means of keeping the armature down, via a ratchet. 

Latching relay Relay that can be mechanically latched in a given position when operated by... 

This is the ultimate safety related system and, in general, will be used only when other systems (or practices) have failed. The emergency stop system is basically a loop which, if broken, causes a latching relay (referred to as relay Kl) to drop out. This relay controls... 

Similarly, a set of relays wired in parallel can be used to implement the OR condition shown in Fig. 22.6b. Here actuation of any one or more of these input relays will cause the output to be actuated. To illustrate NOR or NAND gates in ladder logic, slashed contacts are drawn. In binary logic diagrams, a small circle is appended to the OR or AND symbol. These contacts are then normally closed rather than normally open, as is the case shown in Fig. 22.6. Sequencing operations typically require the use of latching relays (which hold a... 

The PLC controller mentioned earlier is used basically for regulating industrial processes or to replace relay controllers (latching) in electrical... 

Now let s look at the coils inside the relay. The coils in the relay are normally DC activated only through a bridge rectifier, (see circuit drawings of AC relays and note the diamond shaped symbol for a bridge rectifier). They function as a switch to open the circuit, which stays open as long as the inverter is turned on. (one Click). If the relay is working on AC current it will buzz as the latching is switched back and forth. 

Also in normal 2 coil relays, the coils are mounted in a U shape with the cores connected across the bottom mounting plate. This configuration would allow for both S1 and S2 latching. In S1r9a9m9 s drawing, the second coil would have reverse polarity and thus would not latch properly as shown. 

Uses. Hard ferrites are used widely in electromechanical devices, e.g., generators, relays, motors, and magnetos electronic applications, e.g., loudspeakers, traveling-wave lubes, and telephone ringers and receivers aniitheft tags, holding devices such as door closers, seals, and latches ... 

Note that it is not necessary to use a latching or self-holding relay. A single impulse to the relay s activating coil will cause disruption... 

RLY 1, RLY 2 latching open frame relay 12 vdc coil - 4PDT 10 amp contacts 20 amps total capacity Surplus Sales of Nebraska (KO)110636 2... 

Sheet 1 shows the summation of the sub-safety circuit relaying on the VSR power supply battery and the latching circuit Also shown is the... 

The latches are also of fail-safe design, because loss of eiectri cal power or burnout of the latch solenoids will permit the rods to drop. The IXX safety circuit utilizes two sets of closed contacts in series from the primary sensing elements such as power relays, Beckmans, Paneilit, etc. The opening of any one contact will de-energize the associated IXX or IXXA relay and scram the VSR s, This is a form of parallel redundancy. In this case, fail safe operation, i,e rod insertion, will occur for almost any circuit contact or relay malfunction. 

On the top of page 137, positive feedback in a relay system was seen to lead to a "latched" condition, where the relay continues to feed operating signals back to itself and therefore continue in one position, until the current is somehow interrupted by some other action. It should be noted, however, that when a relay armature operates, it hits the "normally open" contact, which is a hard barrier to any further motion. It might bounce back a little bit, but it can not "overswing." Therefore, positive feedback leads to stable latching and no further motion. 

System operation is started by momentarily depressing switch 51. This applies power to the coil of relay K, thus closing K contacts. Relay K is now electrically self-latched. The closure of relay K contacts allows power to be applied to the coil of relay K2, whose contacts close to start up the pump motor. 

Relay A device operated by a variation in the conditions in one electric circuit to effect the operation of other devices in the same or other circuits. Examples include current, latching, magnetic control, magnetic overload, open-phase, low or undervoltage, and overload. 

Different types of electrical equipment are assigned letters for identification all relays, breakers, and timers are lettered K pushbuttons are lettered P, or N if they latch in bypass switches are... 

Shown here are two overrides (pneumatic devices illustrated). One has a latch-up circuit with a gain 25 relay, which provides a high signal the first time the reboiler is filled with liquid the steam valve is held closed until the level covers the tubes. Once latched up this circuit does not function again until it is unlatched by switching to shutdown. ... 

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