Variable Voltage Regulator

The Variable Voltage Regulator makes variable voltage supplies from 0-11 KV or any desired voltage upto 5000 kva. These variable voltage supplies are used for special purpose applications and testing. Our Variable Voltage Regulator has been designed, manufactured and tested with proper care and attention, to give efficient service. Voltage Regulator/Regulating units manufactured by us comply with IS: 1180 and IS: 2026 as far as applicable.

Principle of Operation :

• The Variable Voltage Supply/ Regulator consist of following basic components depending on the rating of the equipment.
• Step up Transformer
• Buck boost transformer
• Rolling contact type voltage regulator
• Automatic control gear
• Figure shows 2000 KVA capacity Variable Voltage Supply/ Regulator with constant Input voltage of 11 kv and variable output voltage from 0-11 kv. It consists of a Step up Transformer, 2 nos. Regulators and Buck Boost transformer. This circuit is normally used to Vary on load voltage when the regulator used in conjunction with buck/boost transformer and step up transformer.
• The equipment are available with following control devices:
• Manual version
• Motorised version
• Remote control
• In manual version a Hand wheel / T – Handle is provided and desired output voltage can be obtained by rotating the Wheel / Handle manually.
• In case of motorized version and servo motor will be provided which can be operated by two sets of push buttons or toggle switch for raising and lowering the output voltage.
• In case of remote control arrangement one extra set of push buttons will be provided in your main panel from where the operator would be able to maintain the desired voltage with the help of those push buttons.

Description-Rolling Contact Regulator
This is essential a Continuously tapped auto wound transformer having helical coils mounted on a conventional laminated transformer core. However, the regulating winding is designed as a single layer type giving longer and slimmer version of the transformer coil but in principal it is the same.

The regulating winding is varnished and baked to improve rigidity and ensure that the construction is non hydroscopic. After proper treatment longitudinal/track is ground on the coil to form a bared copper surface with the winding wire covering providing inter turn insulation. Graphite rollers , assembled on carrier boards, traverse throughout the length of the coil track. These rollers are connected electrically with the output terminals and as they are driven over the track a variable voltage is obtained.

The Regulator may be of one sided or can be made double sided. In case of double sided Regulator both side of regulating winding is bared and allows rollers to be driven in opposite direction on either side of the coil. In such cases carrier boards are provided on both sided of the coils and the output terminals will be taken out though balancing transformer.
The contact carrier is driven by a hand wheel / T–Handle or motor which is coupled to the chain drive. Limit switches operated by the carrier board are fitted to prevent over run. In case of your specific requirement additional limit switches will be fitted for minimum position inter-locking along with the auxiliary circuit. The power supply of the motor is derived from the Regulator unless otherwise specified. The entire regulator assembly is housed inside a rigid M.S. Tank filled with oil. The Hand wheel / T – Handle, Motor push buttons etc. is fixed up inside a separate sheet steel box, which is attached to the main tank. Wherever automatic control is required, the solid stat voltage-sensing relay is also provided inside a sheet steel box fitted along with the regulator tank.

In VOLTAGE REGULATING UNIT the equipment consist of Regulators and Transformers are explained earlier. The description of the Regulator has already been described above. The Transformer (buck/boost and step up) are of conventional design as per IS: 1180 or IS:2026. The Regulator is combination with transformer gives the desired regulation of the voltage in case of higher capacity and H.T equipment. Some times in Low Voltage higher capacity units the regulator and the transformers are enclosed inside a single tank, however, in case of a high voltage higher capacity units the regulator is housed inside a separate tank and transformer is housed in another tank. A separate instruction and maintenance manual for the transformer is enclosed here with which will be applicable only to the transformer part of the regulating unit.