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How does across the line starting work?
There are mainly two types of starting methods. Reduced voltage starting and across the line starting. Reduced voltage starting comes in the configuration of the wye-delta starter. Across the line starter is the combination of voltage source, motor contactor and motor load. The utility company's policy is set, to allow only a certain horsepower load to utilize across the line starting. This is in the neighbourhood of 25 HP up to 50 HP. High horsepower loads draw high current, up to 600%, of the motors full load rated amps. This high current inrush tends to draws the line voltage down and to prevent this condition wye-delta starters must be used. In the electrical market today solid state soft starts have taken the place of wye delta starters. When using a three phase contactor across the line for motor starting, a three phase overload block must be used. The wiring of the contactor consists of taking L1, L2 and L3 of the supply voltage and connecting it to the top of the contactor on terminals L1, L2 and L3 of the contactor. The motor load is connected to T1, T2 and T3 on the bottom of the overload block. If you are using a three wire control for operating the contactor, the contactor must have a N.O. contact on it to seal the contactor in once the contactor coil has been energized. The overload block has three N.C. contacts, one for each leg of L1, L2 and L3. These three contacts are wires in series to the stop - start circuit. Years ago on old schematic diagrams these contacts used to be placed on the down stream side of the magnetic starter's coil (between the coil and the neutral). When the overloads tripped the voltage was left on the control circuit which was found to be dangerous for trouble shooting. Now for safety reasons, the overload contacts are positioned in the beginning of the start- stop circuit so that when a overload trips, the whole stop - start circuit becomes de-energized.
Why use link in star contactor?
The link in the star contactor is used to form the star point of three of the motor leads. On most star wound motors the star point is inside the motor windings. On a motor that can be used for star delta starting it is a six wire motor. The star point winding depends on the contactor to tie the coil ends together externally in the control panel of the star delta starter.
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 is a timer in a star delta starter?
A timer in star delta starter for a three phase motor is an electronic device designed to do the change over or transition from star connection - using which the motor suns on a reduced voltage and current and produces less torque - to the delta connection necessary for running the motor at its full power, using high voltage and current to produce a high torque. The timing interval that is set is dependent how long the motor needs to start up from standstill to normal speed. Some motors require 15 seconds for the initial startup in star connection and after that given value of time the timer signals to the star contactor to go to the open position and the main delta contactor to go to the closed position, thus forming the delta circuit.
Which is the largest of three transistor current?
Emitter current is the sum of collector current & base current , hence the largest. Base current is the smallest.
How many paths can electricity take in a parallel circuites have a battery and three light bulbs?
If each lamp is connected in parallel, then there are three 'paths' that draw current from the supply.
On an electrical three phase contactor what is A1?
A1 is a termination point on a contactor it is an alseriery going to another point.
Up to how many paths can an electric current follow?
There is no limit. If you have a TV, a light and a refrigerator, electric current can go through all three.
What are the parts of magnetic contactor?
There are three main parts of a magnetic contactor. These include the power contacts, contact springs, and the auxiliary contacts.
Can you put one phase of a three phase ditribution board through a contactor so that the other phases stay on?
Yes, but you must have your neutral wire to form a return path for your current.
Can a 3 phase contactor be wired for single phase?
Yes, L1 of the single phase supply is terminated under terminal L1 of the three phase contactor. L2 of the single phase supply is terminated under terminal L2 of the three phase contactor. A conductor from output terminal T2 is then taken to input terminal L3. The single phase load is then connected to the contactor's output terminals T1 and T3. This incorporates all three of the overload blocks on the contactor into the control circuit. With the overloads in the control circuit, if an overload occurs the magnetic contactor's holding coil will drop out and take the load off line.
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 a basic elements of a pneumatic system work?
A connection of a contactor to three phase motor.
How many wires to control a mechanically held contactor?
A contactor is a type of switch. However this switch uses electricity to power an electromagnetic coil to switch on or off power. Hence a contactor needs 2 wires - A live/hot wire and a neutral wire. Generally these are connected across the A1 and A2 terminals of the contactor.
How does across the line starting work?
There are mainly two types of starting methods. Reduced voltage starting and across the line starting. Reduced voltage starting comes in the configuration of the wye-delta starter. Across the line starter is the combination of voltage source, motor contactor and motor load. The utility company's policy is set, to allow only a certain horsepower load to utilize across the line starting. This is in the neighbourhood of 25 HP up to 50 HP. High horsepower loads draw high current, up to 600%, of the motors full load rated amps. This high current inrush tends to draws the line voltage down and to prevent this condition wye-delta starters must be used. In the electrical market today solid state soft starts have taken the place of wye delta starters. When using a three phase contactor across the line for motor starting, a three phase overload block must be used. The wiring of the contactor consists of taking L1, L2 and L3 of the supply voltage and connecting it to the top of the contactor on terminals L1, L2 and L3 of the contactor. The motor load is connected to T1, T2 and T3 on the bottom of the overload block. If you are using a three wire control for operating the contactor, the contactor must have a N.O. contact on it to seal the contactor in once the contactor coil has been energized. The overload block has three N.C. contacts, one for each leg of L1, L2 and L3. These three contacts are wires in series to the stop - start circuit. Years ago on old schematic diagrams these contacts used to be placed on the down stream side of the magnetic starter's coil (between the coil and the neutral). When the overloads tripped the voltage was left on the control circuit which was found to be dangerous for trouble shooting. Now for safety reasons, the overload contacts are positioned in the beginning of the start- stop circuit so that when a overload trips, the whole stop - start circuit becomes de-energized.
How do you make a 30HP three phase motor connection?
From the bottom of the motor contactor's heater block you connect the motor's leads to T1, T2 and T3. If the motor rotates in the wrong direction reverse any two leads on the bottom of the motor's contactor heater block.
You found a 220volt coil on a 3 phase motor contactor and the one side of the coil is feed from B phase and the other side is also feed from B phase it would not pull in the contactor?
your not completing the circuit your only using one phase for a three phase motor
