0
You put a diode in parallel with the coil. The cathode end of the diode connects to the plus side of the coil and the anode connects to the negative side. The cathode is usually marked with a line at one end of the component.
Wiki User
∙ 13y ago
Add your answer:
Earn +20 pts
How do you reduce induced voltage in control cables?
You can reduce induced voltage in control cable by applying the following methods. 1. While laying control cable keep a minimum distance 300mm from the power cable. 2. If possible try to lay control cable on the separate cable tray. 3. Earth the Armour/ screen of the control cable on both side of the cable or at-least at one side. Some times it is not important to reduce the the induced voltage in control cable, but it's effect on relay or contactor as the contactor or relay does not pick-down even after the removal of the control supply. In that case it is recommended to use two relay/contactor in parallel and use the contacts in series or parallel for control circuit interlocking.
Schematic for a slow releasing relay?
Are you talking about delaying the release of a relay? or actually slowing down the mechanism so it doesn't "Click". You'll NEVER get rid of the click, the inside of that consists of a metal arm attached to a spring. When current is applied, an electromagnet pulls the arm toward it and completes the circuit, it snaps because this happens very quickly. When the current is removed the spring snaps it back into its original place. If you want to slow down the release, put a capacitor and resistor in front of it. The capacitor stores the charge, while the resistor limits how fast it discharges. The actually capacitor values and resistor values will vary with how much current needs to be applied to keep the relay closed, and the length of time you want to keep it that way. (+)-------[Capacitor]-----[Resistor]------<Your Relay>--------(-)
Should a motor with a start capacitor have a start relay?
The compressor motor employs both a start and run winding. The run winding is energized during the complete cycle of operation, whereas the start winding is energized only during the starting period. The current-operated type of relay has a coil connected in series with the run winding of the compressor. Some current-operated relays plug directly onto the compressor while others do not. Most relays are mounted in a case located on the compressor. When the thermostat closes, the compressor attempts to start, drawing heavy current through the run winding and the relay coil. This strong current flow through the relay coil creates a magnetic field strong enough to cause the start contacts to lift and close, energizing the start winding. When the compressor reaches approximately 3/4 running speed, the current flow through the relay coil decreases (due to the countering electrical magnetic field in the motor) and as the magnet weakens, the start contacts fall open. This type of relay must be used with an overload protector and must be mounted in an upright position, so that the contacts can fall freely to the "open" position.
What is pu in regard to relay settings?
PU stands for pickup. It is one of the many settings that are used while trying to set the right relay.
Which is more useful static or current electricity?
It is current. Because current electricity has moving charges while static electricity has stationary charges.
How can you replace a diode with a relay in a circuit?
In certain cases, yes. A diode is a valve for current. A relay is a switch that is actuated by current. If you have a flow of current going from A to B and you only want it to go from A to B you can use a diode in series between A and B. You can also use a switch in series between A and B that is controlled by a relay that is in parallel with the switch. Add a large resistor in series with the relay so that it does not permit too much current to back flow through it. Configure the relay to open the switch when the current is trying to go from B to A and to close when the current is trying to go from A to B. This is not a leak free valve. Current will be going back through the relay while it is holding the switch open. As mentioned put a large resistor in series with it to reduce this. You cannot have this resistance too large though or the relay will not have enough current to maintain the switch. Another caveate is that this will not be a fast acting valve. There will be some time during current direction changes when the switch will be spending time openning and closing. It is a mechanical switch after all.
What is the difference between diffrencial relay and a distance relay?
They're completely different, used for different applications (usually). A distance relay uses both current and voltage. A differential relay uses only current. A differential relay usually has harmonic restraint capability, while distance relays ideally track system frequency. Differential relays require fast operation, while distance relays may not be required to operate as quickly. Distance relays have more issues with operating for out of zone problems than differential relays. There are many more, but this gives an idea.
What conclusion can you make about how resistance affects current in a wire?
You can solve Ohm's Law for current.Ohm's Law: V=IRSolving for current: I = V/RIn other words, more voltage will cause more current, while more resistance will reduce the current.
Should you wear zero power spectacles while using computer?
If you need glasses, you should wear whatever glasses reduce eye strain while using the computer. If you are going to use zero power, then just do not wear any glasses at all.
WHAT IS type 2 coordination chart?
To understand various considerations for proper co-ordination, time-current characteristics of thermal overload relay (curve B), H.R.C. fus (curve C), MCCB with only instantaneous release (curve D) and MPCB (curve E) are superimposed on motor starting characteristics (curve A) in Fig. 3. Intersection of characteristics of thermal overload relay and Fuse / MCCB is termed as 'cross-over point' and corresponding current as 'cross-over current' lco. Following points are to be ensured while selecting components to have properly co-ordinated motor protection: lContactor rating (AC-3) should be more than or equal to motor full load current (if application is AC-3 duty) Thermal overload relay of appropriate 'Trip Class' is selected. Time current characteristics of the relay should remain above motor starting characteristics as shown in Fig. 3. For fault currents lower than 'cross-over current lco', relay will respond faster than SCPD and hence contactor will interrupt the fault current. Fault currents higher than lco will be interrupted by SCPD. Hence, rating of contactor is so chosen that lco is less than rated breaking capacity of the contactor Relay and contactor should be able to withstand lco for a duration equal to trip time of the relay. IEC / BS / EN standards require that the contactor should be able to withstand at least current equal to 8 times AC-3 rating (6 times for ratings higher than 630A) for 10 seconds While using MCCB or MPCB, attention needs to be given to motor peak starting current. To avoid operation of MCCB / MPCB during starting, instantaneous release is chosen as 12 times the full load current of the motor. This thumb rule assumes motor starting current equal to 6 times full load current In case of high efficiency motors, starting currents could be about 8 times full load current. For such application, MCCB rating need to be selected such that instantaneous release setting is higher than 12 (about 14) times full load current to avoid nuisance tripping during starting. Similarly, while using MCCB as a SCPD for Star-Delta starter, consideration needs to be given to peak current associated with change over from Star to delta. Instantaneous release of MPCB is normally set at 12 times the rating. Hence, possibility of nuisance tripping needs to be considered while using MPCB for protection of high efficiency motors or for star delta starter.
Why scr is not suitable for dc circuit?
A: It is OK if a way to insure that the SCR can be shut off otherwise it will conduct forever. the only way to shut off an SCR while is on is to reduce the current below them holding current point or by reversing the polarity briefly
Does the current really pass through us while using a tester?
The testing instrument's casing and grip/handle should be fully insulated from the current it is testing. If it was not then the current that would pass through you would be recognized as an electrical shock.
How do you remove a rounded off nut from a bolt?
try using vice grips to hold the nut while you use a wrench on the bolt Using 6 point sockets or wrenches will help reduce that situation from happening.
Why voltage is low while using heater as home appliance?
The current is proportionately high as heater requires current to heat the filament.The voltage is deliberately low to sustain the safe power consumption limits.
What would be the effect on the profit of an accounting period if a drawing of 100 was accounted for as an expense by mistake?
If drawings are shown as expenses then it will reduce the current year's profit while it will overstated the capital of company as well.
Will a main relay malfunction cause the car turn off while driving?
Yes, the main relay is also known as the fuel pump relay. When one fails in can create a slue of different problems for the car such as turning the car off while driving.
Why carbon cannot reduce Al from its oxide while it can reduce Zn from its oxide?
activity series
