Which side of a motor contactor should the overload contact be placed?

Can you start 20kw motor on direct on line circuit?

No, the motor has to be connected to the line voltage through a set of fuses and then an electrical contactor. Also the motor must be thermally protected against overloads by using an overload block or heaters. This is to allow the motor contactor to drop out is a overload fault should occur.

What melts if the current in an electric circuit gets too high?

Anything that is in contact with the medium conducting the over-current. In an ideal situation a breaker should trip or a fuse should blow. If not wire insulation can melt, the wire itself can melt or various components can either melt or burn outright. Sq D used a motor overload heater that was used on its motor overload contactor. It was designed as a ratchet on the end of a shaft that was inserted in a barrel on the body of the overload. A melting alloy held the shaft in the barrel. The ratchet on the end of the shaft held a spring loaded contact in the closed position. The body of the overload was bolted in series with the load terminal on the output side of the contactor. When the motor load current heated the overload protection device above its trip point, the alloy melted allowing the shaft to turn in the barrel portion of the overload heater. Being spring loaded the ratchet turned from the spring pressure and opened the normally closed contact thereby opening the magnetics coil circuit, dropping the contactor open and shutting the motor off.

How do you wire a DOL starter controlled by a pressure switch for a water pump?

Answer for USA, Canada and countries running a 60 Hz supply service.The wiring of this type of installation is quite elementary. It is all about the control voltage for the magnetic contactor and having the pressure switch in series with the contactor's coil.If the pump supply voltage is 120 volts, take a wire from L1 on the contactor and place it on the normally closed contact point on the overload block.From the N.C. contact on the overload block take a wire to one side of the pressure switch.From the output side of the pressure switch contact take the wire back to one side of the contactor's coil.Connect the other side of the contactor's coil to the neutral wire from the supply.Now you will have three components in series with each other. The overload block, the pressure switch and the contactor's coil as the load of the circuit. When the pressure switch closes due to low pressure the coil will be energized.If the pump motor goes into an overload condition, the overload block contacts will open and de-energize the contactor's coil and the pump will shut off.As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.Before you do any work yourself,on electrical circuits, equipment or appliances,always use a test meter to ensure the circuit is, in fact, de-energized.IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.

How do you connect float switches for a single phase motor through contactor and Over Load Relay?

you would wire a float switch into the control circuit i.e, the contactor coil (which is relatively low current but rated at least for the control voltage,, in most cases 120VAC). also in the same circuit would be the overload contacts. if the overload trips and/or the float switch opens then voltage is removed from the contactor coil

What is the circuit for float switch connection to a single phase motor?

float switches are not rated for motor currents, therefore you would need a motor starter/contactor to handle to motor current and the float switch would be wired into the coil circuit, i.e., control voltage source.. I'm guessing 120VAC wired through the float switch to the contactor coil and the other side of the coil wired through the overload contacts to neutral (white wire).

How do you wire a pump start relay for 220 volts?

Assuming that your pump start relay is a contactor with overload protection and a 220 volt coil. Connect the incoming 220V to the connection points on the top of the contactor. Connect the pump motor to the bottom contactor connection points. From the right incoming voltage connection point take a # 14 wire, in flexable conduit, to one of the N.C. (normally closed) terminals in the pressure switch. The pressure switch which should be connected into the water line at this time on the pressure side of the pump. From the opposite N.C. terminal in the pressure switch take another # 14 wire, in the same flexable conduit, to one side of 220V contactor coil. At this point, (1) if overload contacts are available, take a # 14 wire from the other side of the 220V contactor coil to one side of the N.C. contacts in the overload block. From the opposite side of the N.C. contact in the overload block take a # 14 wire up to the left side of the incoming 220V connection point. If there is no overload block, as some motors have internal overload protection, (2) take a # 14 wire from the other side of the 220V contactor coil directly to the left side of the incoming 220V connection point. As you can see the circuit is all series connections from voltage supply to pressure switch, to overloads, to return voltage supply. With the pressure switch contacts closed and the overload contacts NOT tripped the pump will start. When pressure reaches the set point the switch will open and the pump will shut off.

Can you use normal relay to start a single phase motor pump?

It depends on what your definition of a normal relay is. If it is a small plug in relay to control the motor's contactor then there is no point. All pump motors need control to start and stop the pump. Whether it is done from a pressure switch or a float system it doesn't matter they both should control the motor's contactor and not the pump directly. Most small relays do not have the amp capacity in their contacts to handle inductive loads. Using a motor contactor also has the benefit to protect the motor with overload protection. Using the overload contacts in series with the control device allows the pump to go off line should an overload occur.

What is the Difference between a magnetic starter And a contactor?

Motor starter usually refers to the complete assembly, including enclosure, contactor, control transformer (if any), overloads, fuses (if any), etc. A contactor is really just an overgrown relay, and is just one component of a starter. That having been said, many folks use the two terms somewhat interchangably. So someone who says starter may mean contactor, and vise-versa. Go figure.

How do you connect a 9-wires 3-phase motor?

Incorrectly connecting a multi-phase motor could potentially cause a huge problem. Inside of the cover where the motor leads reside (we call them 'pigtails') is a diagram of the lead connections. They are wired for typically either 230V or 460 Volt AC operation

What components can be changed on a contactor and a starter for rebuilding purposes?

Various components can be added and removed from a contactor. Auxiliary contacts can be inserted in front of the main contacts, as well as a time relay in the case of motor starters (star/delta starter). Usually you should fit a overload relay when you use the contactor in a motor starter, this is inserted in the main contacts at the bottom. However, the internal components like the coil may never be changed or replaced.

How do you wire a three phase forward - reverse starter?

You start with a normal one way circuit consisting of a three phase contactor and an three phase overload in series for the forward circuit. Then you add the reverse contactor in parallel with the forward contactor but with line one and line two crossed over i.e. when the reverse contactor is made, line one of the supply will be connected to line two of the motor and line two of the supply to line one of the motor. The control circuit must also be interlocked to prevent forward and reverse being energized at the same time.

What should the resistance on a 30 amps triple pole contactor measure?

If the coils pulling the contactor in, you should have negligible resistance. If the contactor is not in, then you should have open circuit. Unless your measuring the resistance of the coil, in which case it will roughly be around 30ish ohms im guessing, depends on the coil voltage

Which side of a motor contactor should the overload contact be placed?

Add your answer:

How do you wire a DOL starter controlled by a pressure switch for a water pump?

How do you connect a 9-wires 3-phase motor?

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In a typical 2 ton air conditioning unit what voltage engages the point of the contactor?

How do you wire a 240 volt single phase magnetic starter to an air compressor?

Can you start 20kw motor on direct on line circuit?

What melts if the current in an electric circuit gets too high?

How do you wire a DOL starter controlled by a pressure switch for a water pump?

How do you connect float switches for a single phase motor through contactor and Over Load Relay?

What is the circuit for float switch connection to a single phase motor?

How do you wire a pump start relay for 220 volts?

Can you use normal relay to start a single phase motor pump?

What is the Difference between a magnetic starter And a contactor?

How do you connect a 9-wires 3-phase motor?

What components can be changed on a contactor and a starter for rebuilding purposes?

How do you wire a three phase forward - reverse starter?

What should the resistance on a 30 amps triple pole contactor measure?

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