MCC Panel

Motor Control Center Panel

Popularly termed as the Starter Panel, MCC Panel, Motor Control Panels are very important part of our product catalogue as far as Power Panels are concerned. We offer highly efficient MCC Panels that are made from premium raw materials and electrical components sources from reliable partners. Designed by our in house research and development division, these Motor Control Panels comply with internationally accepted and nationally prescribed quality and performance guidelines. GRM is counted as one of the forefront Motor Control Center Panel Manufacturers, Suppliers and Exporters from India.Moreover, our experts also use latest technology and advanced mechanics to cater to the evolving needs of clients and the challenges faced by them. Available in different capacities, specifications and multiple power stabs, our Motor Control Panels are capable of supporting high capacity industrial grade motors. We also test these Motor Panels before delivering them to clients for quality, functional output and safety standards.

A motor control center (MCC) is an assembly of one or more enclosed sections having a common power bus and principally containing motor control units. Motor control centers are in modern practice a factory assembly of several motor starters. A motor control center can include variable frequency drives, programmable controllers, and metering and may also be the electrical service entrance for the building.

A Starter is a device that controls the use of electrical power to equipment, usually a motor. As the name implies, starters "start" motors. They can also stop them, reverse them, and protect them. Starters are made from two building blocks, Contactors and Overload Protection.

        Contactors control the electric current to the motor. Their function is to repeatedly establish and interrupt an electrical power circuit.

        Overload Protection protects motors from drawing too much current, overheating, and from literally "burning out".

A starter turns an electric motor or motor controlled electrical equipment on or off, while providing overload protection. Starters represent another in motor control applications. The two main types of starters are Manual Starters and AC Magnetic Motor Starters, commonly known as Motor Starters.

DOL Starter

Direct On Line StarterDifferent starting methods are employed for starting induction motors because Induction Motor draws more starting current during starting. To prevent damage to the windings due to the high starting current flow, we employ different types of starters.The simplest form of motor starter for the induction motor is the Direct On Line starter. The DOL starter consist a MCCB or Circuit Breaker, Contactor and an overload relay for protection. Electromagnetic contactor which can be opened by the thermal overload relay under fault conditions.Typically, the contactor will be controlled by separate start and stop buttons, and an auxiliary contact on the contactor is used, across the start button, as a hold in contact. I.e. the contactor is electrically latched closed while the motor is operating.

Principle of DOL:

To start, the contactor is closed, applying full line voltage to the motor windings. The motor will draw a very high inrush current for a very short time, the magnetic field in the iron, and then the current will be limited to the Locked Rotor Current of the motor. The motor will develop Locked Rotor Torque and begin to accelerate towards full speed.

Provided the torque developed by the motor exceeds the load torque at all speeds during the start cycle, the motor will reach full speed. If the torque delivered by the motor is less than the torque of the load at any speed during the start cycle, the motor will stops accelerating. If the starting torque with a DOL starter is insufficient for the load, the motor must be replaced with a motor which can develop a higher starting torque.

DOL starting have a maximum start current and maximum start torque. This may cause an electrical problem with the supply, or it may cause a mechanical problem with the driven load. So this will be inconvenient for the users of the supply line, always experience a voltage drop when starting a motor. But if this motor is not a high power one it does not affect much.

Parts of DOL Starters:

Contactors & Coil.

Magnetic contactors are electromagnetically operated switches that provide a safe and convenient means for connecting and interrupting branch circuits.

Magnetic motor controllers use electromagnetic energy for closing switches. The electromagnet consists of a coil of wire placed on an iron core. When a current flow through the coil, the iron of the magnet becomes magnetized, attracting an iron bar called the armature. An interruption of the current flow through the coil of wire causes the armature to drop out due to the presence of an air gap in the magnetic circuit.

Line-voltage magnetic motor starters are electromechanical devices that provide a safe, convenient, and economical means of starting and stopping motors, and have the advantage of being controlled remotely. The great bulk of motor controllers sold are of this type.

NO-normally open

NC-normally closed

Over Load Relay (Overload protection).

Overload protection for an electric motor is necessary to prevent burnout and to ensure maximum operating life.

Under any condition of overload, a motor draws excessive current that causes overheating. Since motor winding insulation deteriorates due to overheating, there are established limits on motor operating temperatures to protect a motor from overheating. Overload relays are employed on a motor control to limit the amount of current drawn.

The overload relay consists of a current-sensing unit connected in the line to the motor, plus a mechanism, actuated by the sensing unit, which serves, directly or indirectly, to break the circuit.

Star Delta Starter

STAR DELTA STARTER starting method that reduces the starting current and starting torque. Star delta starter design normally consists of three contactors, an overload relay and a timer for setting the time in the star-position (starting position).

For the star delta starter, a motor must be in delta connected during a normal run and the main purpose is to be able to use star delta starter.

Star delta starter received the starting current is about 30 % of the starting current during direct on line start and the starting torque is reduced to about 25 % of the torque available at a D.O.L start.

Star delta starter only works when the application is light loaded during the start. If the motor is too heavily loaded, there will not be enough torque to accelerate the motor up to speed before switching over to the delta position.

Description of Star Delta Starter Operation

For star delta starter,the basic function is to enable the motor to start and the motor windings are configured in a star formation to the supply voltage.

The voltage applied for star delta starter to the individual motor winding is therefore reduced by a factor of 1√3 = 0.58 this connection amounts to approximately 30% of the delta values. The starting current is reduced to one third of the direct starting current.

Due to the reduced starting torque, the star-delta-connection is suitable for drives with a high inertia mass but a resistance torque which is low or only increases with increased speed. It is preferably used for applications where the drive is only put under a load after run-up.

After motor run-up, in most cases an automatic timing relay controls the switch-over from star to delta. The run-up using star connection should last until the motor has reached the approximate operational speed.so that after switching to delta, as little post acceleration as possible is required. Post-acceleration in delta connection will instigate high currents as seen with direct on-line starting.

The duration of start in star connection depends on the motor load. During delta connection, the full mains voltage is applied to the motor windings.

How it works?

There are two contactors that are close during run, often referred to as the main contactor and the delta contactor. These are AC3 rated at 58% of the current rating of the motor. The third contactor is the star contactor and that only carries star current while the motor is connected in star. The current in star is one third of the current in delta, so this contactor can be AC3 rated at one third of the motor rating.

In operation, the Main Contactor (KM3) and the Star Contactor (KM1) are closed initially, and then after a period of time, the star contactor is opened, and then the delta contactor (KM2) is closed. The control of the contactors is by the timer (K1T) built into the starter. The Star and Delta are electrically interlocked and preferably mechanically interlocked as well. In effect, there are four states:

OFF State. All Contactors are open

Star State. The Main and the Star contactors are closed and the delta contactor is open. The motor is connected in star and will produce one third of DOL torque at one third of DOL current.

Open State. The Main contactor is closed and the Delta and Star contactors are open. There is voltage on one end of the motor windings, but the other end is open so no current can flow. The motor has a spinning rotor and behaves like a generator.

Delta State. The Main and the Delta contactors are closed. The Star contactor is open. The motor is connected to full line voltage and full power and torque are available.

DC Starter Panels

Our organization is amongst the prominent manufacturer and supplier of best quality range of DC Starter Panel. We are offering these DC starter panels that are very durable and highly efficient renowned for its trouble free operation and smooth functionality. These DC starter panels are able to provide consistent electrical supply without disturbances and interference from start current. Our DC starter panels have excellent compact designs and supreme efficiency. Avail from us our DC starter panels at reasonable prices.

Features:

• Excellent quality
• Robust
• Easy installation
• Highly efficient
• Rated by current (amperes) or power (horsepower)
• Remote ON/OFF control
• Motor overload protection
• Starting and stopping (electrical life)
• Plugging and jogging (rapid making and breaking current)