Rectifiers are Electrical Machines that are used to convert AC Power Supply to DC Power Supply

VEM designs and manufacturers Rectifier units for three phase, 50Hz AC input supply and suitable for operation at any voltage between 360 to 440 volts.

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Components of VEM Rectifier:

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A.C. Input:

The input to the unit is to be connected through a switch fuse unit of proper rating.

D.C. Output:

For any input voltage between 360 and 440 volts and for any load between zero and its rated full load, the D. C. output is continuously and steplessly changeable from zero to the full rated voltage. The output has a very low ripple content (about 5%), making these units ideal for any specialised procedures like chrome plating or hard chrome plating where low ripple content is required..

Circuit and Components:

These rectifier units use an easy-to-use, universal circuit. Supply is delivered to the continuously variable voltage auto transformer known as the Dimmerstat, which then employs H. R. C. fuses to supply a variable voltage to the primary of a three phase double wound Delta/Double Star linked transformer. Silicon Diodes are used to connect the transformer's secondary to a hexa-phase coupled rectifier. Through an interphase transformer, the output is obtained from the rectifier and the star points of the transformer. The output voltage and output current can be measured using a moving coil voltmeter and an ammeter with a shunt.

a) Dimmerstat:

In procedures involving electro deposition, output is crucial. In comparison to other control methods like resistance boards, tap switches, etc., "VEM" provides a stepless and continuous modulation of output voltage. With the aid of Dimmerstat, a Continuously Variable Voltage Auto Transformer produced by "VEM," the step-less variation is accomplished. Dimmerstat offers a step-less, on-load, uninterrupted adjustment of output voltage without any power loss, in contrast to conventional output control techniques.

b) H.R.C Fuses:

On the primary of the Main transformer, there are special High Rupturing Capacity (H.R.C.) fuses available. These fuses only blow when there is an output overload, a short circuit, or an internal short circuit, hence only H.R.C. fuses with the same rating should be used in their place.

c) Double Wound Transformer:

The double wound transformer used in the Rectifier is of typical design and complies with the insulation requirements and temperature rise requirements of IS 2026. Two secondary windings feature star connections, whereas the primary is connected by a delta winding.

d) Interphase Transformer:

The Interphase Transformer (IPT) is connected between two star points on the secondary windings of the main transformer; it enhances commutation by raising the rating of the rectifier.

e) Rectifier:

The Rectifier is composed of durable Silicon diodes that have been generously rated and are set up in a six phase circuit. The diodes are installed atop cooling fins to disperse heat and raise their efficiency rating.
The necessary number of diodes is connected in parallel depending on the output current rating.

f) Metering

To display the output voltage and output current, a separate panel is equipped with a voltmeter and an ammeter. To make it simple to operate with the Dimmerstat, the panel is positioned on one of the tanks.
The external shunt, which is installed inside the tank, is used in conjunction with the ammeter. All the components in the Rectifier Unit are assuredly supported by 'VEM's renowned after-sales service.

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VEM designs and manufactures high efficiency, long life Rectifiers which supply constant Direct Current to your loads even when input voltage experiences  fluctuations. 

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