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What is the difference between current relay and potential relay?
Wiki User
∙ 13y ago
I think what you mean to ask is; "The difference between a current sensing, and potential sensing relay. I've never heard of a potential relay. Relays are "pulled in" by applying voltage to the coil, typically 120Vac, or 24Vdc. A current sensing relay will close its contacts when it is wired to sense a particular amount of current. Instead of applying voltage (turning on) the relay, it closes contacts when current flows through it.
HVAC technician
***** A 'current' relay has a coil of low resistance wire (heavy gauge wire, few turns), and is energised only by a large current, such as the initial current of a motor starting. The relay coil is wired in series with the run/main winding of the motor, and the relay contacts are normally open. As the motor tries to start, the large current closes the relay, which momentarily brings the start/aux winding into circuit, allowing the motor to go. Used for split-phase and capacitor-start motors.
A 'potential' relay has a coil of high resistance wire (light wire, many turns), and is wired in parallel with the start/aux winding, and the relay contacts are normally closed. At initial motor start-up, high curent will flow through both the run and start windings of the motor. As the motor reaches operating speed, the current reduces, and a "back EMF" is produced allowing current to now pass through the potential relay coil, and open the contacts. Used for capacitor-start and cap-start cap-run motors.
Another HVAC technician.
you sound like a real ahole. everyone in the field calls them potential relays, in addition look at a schematic on an AC and you'll find "PR" potential relay. what a dip#hit
Wiki User
∙ 13y ago
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What is the difference between a circuit braker and a relay?
A circuit breaker when energized will latch and stay in that position until the load is reduced and manually reset. a relay will change state continuously if the source continuously changes
How much current a relay coil can withstand?
There are basically two parts to a relay. The control voltage side when energized passes a current through a coil that activates a solenoid and opens or closes a switch. This is typically a small current. The current in the switch should be rated on the device and is usually quite a bit higher than the control current.
How do you wire a 12 volt automotive relay?
there should be a diagram on the side of the relay with the pin numbers and some symbols. the pins that are on the coil or control side can be wired power and ground. this generally goes through a switch. the load side has a small gate looking symbol these can be wired power and ground either way and this is the side that you connect to whatever you are powering on. make sure to use a fuse on this circuit on the power lead.
What is AC rating DC rating wrt Relay contact or contact of contactor?
The contact rating is normally given in AMPs or HP and refers to the load the "switch" in the relay can handle. The manufacture will specify the relay contact rating in the data sheet. This rating depends on the current being controlled by the relay, the connection type (how the relay is mounted) and the duty. A Normally open relay in pilot duty (clicked closed all day) may be only 10% of the same relay in intermitted contact duty. DC current requires a higher contact rating then AC. For example a relay rated at 1A @ 24vdc should also handle 1A @ 120vac and as the voltage increases the contact rating will lessen.
What is a interposing relay?
In general, a DCS or PLC, handles numerous discrete I/Os. One common I/O module (board) is used to supply 8, 16 or more points. Discrete output circuits from a DCS typically use low power level signals (transistors, micro relays) which cannot be sent directly to the field devices such as electromagnetic valves or motor control circuits. That is why interposing relays are often necessary. These relays play an important role by amplifying the current capacity of the contact signal of the I/O module allowing larger current flow. In addition, discrete input circuits normally can handle only dry contacts or wet contacts of low voltage, which also require interposing relays. For example, let's say the relay of a PLC can only accommodate 0.5A at 220 VAC, but the solenoid which is to be connected to the relay requires 1.2A at 220 VAC. In this case, an interposing relay with contacts rated for operation at 1.2A at 220 VAC would be used as an interposing relay "between" the PLC relay and the solenoid. The coil of the interposing relay should require less voltage and current than the driving relay is rated for, and the contacts of the interposing relay must be rated to handle the requirements of the load (solenoid, light, contactor, motor, etc.).
Is a current relay same as potential relay?
current relay are using for over current low state & high state.but potential relay are related to voltage.
What is the difference between an earth fault relay and an over current relay?
earth fault relay is also a type of over current relay but the set value of current or relay sensing current is much less than the maximum load current.in over current relay relay sensing current ise than maximum load current mor
Difference between overcurrent relay and fuse?
Current is flow of electricity charge. Voltage is a measure of potential energy or charge. Fuse. Is a device that opens when the current rating is exceeded this stopping the flow of current.
Difference between overload relay and over current relay?
due to the extension of loads they are using the relays for protection.........
What is the difference between solid state relay and safety relay?
not sure
What is the difference between a relay and an auxiliary relay from constructionapplication poin of view?
I think aux relay is part of relay
Is there a difference between the main relay and the fuel pump relay on the 2000 Honda civic ex?
They are the same relay.
What is the main difference between a relay and a solenoid?
A relay is a switch - a solenoid produces a magnetic field.
Which instrument transformer mostly used in relays?
Both Current and Potential Transformers are used for relays according to the working of relay.
What What is the difference between a humidistat and a dehumidistat?
The difference is the relay operation.Normally opened or normally closed.If you add an external spdt relay,you could have a humidistat/dehumidistat.
Difference between ladder logic and relay logic?
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What voltage does a potential relay operate from?
The voltage for a potential relay will depend on the circuit that the relay is installed in. The relay can be made for low voltages (5v) to higher voltages (440.)
