Products -> Standard Variable Transformers -> Three Phase Variable Transformers – Varivolt Range

	Three Phase Variable Transformers - Varivolt Range

Variable voltage autotransformers (variacs) are an efficient means of varying/controlling AC voltages. Variation of the output voltage is achieved by means of a brush arm with a carbon tip which is rotated on a silver plated commutator, the transformer winding.

Three Phase Variacs consist of three single phase variacs mounted on a common shaft connected in the ‘Star’ vector configuration. The units are aligned along the shaft such that the positions of the brush arms on each unit are matched.

Rotation of the brush arm is performed manually on standard units. The user may vary the output voltage from either zero volts to 100% or 112% of the line voltage, depending on the model and wiring connections used.

Some models are also supplied as standard with a centre tap for use in Buck-Boost systems.

Standard range

Rugged Construction Excellent Regulation High Efficiency No Waveform Distortion Silver Plated Commutator Overload Capacity Low Operating Torque Smooth and Linear Output Low Magnetising Current Negligible Maintenance and trouble free long life

Construction Style
Open	Enclosed
Open style variacs for mounting in equipment panels	Enclosed in painted metal enclosure, rated to IP22

These optional components are installed into auxiliary enclosures that are bolted onto the front panel of the unit

DIMENSIONS

Open Style

Model	Current Rating	Width (mm)	Depth (mm)	Height (mm)	Weight (kg)	Click for Drawing
						pdf	dwg
CMV2F-3	2A	110	125	385	10
CMV5F-3 *	5A	175	200	490	22
CMV8F-3 *	8A	175	200	490	27.5
CMV10F-3	10A	175	200	490	29
CMV15F-3 *	15A	225	250	515	42.5
CMV20F-3	20A	225	250	500	52
CMV28F-3 *	28A	300	360	627	67

Items marked * are built to order other models may be ordered from stock

Enclosed Style

Model	Current Rating	Width (mm)	Depth (mm)	Height (mm)	Weight (kg)	Click for Drawing
						pdf	dwg
CMV2E-3	2A	150	200	410	15
CMV5E-3 *	5A	200	250	505	32
CMV8E-3 *	8A	200	250	505	36
CMV10E-3	10A	200	250	505	38
CMV15E-3 *	15A	250	300	535	55
CMV20E-3	20A	250	300	505	58
CMV28E-3 *	28A	350	400	645	85

Items marked * are built to order, other models may be ordered from stock

Special Designs

If your requirements vary from any of the above standard models, we can provide a bespoke item to suit your application. Such variations may include:-

• Higher currents
• Non Standard Variable Supplies
• Different input voltages
• Different output voltage range
• Motorized drive
• Higher IP rating enclosures

Motor Drive

The motor drive option may be

i) A 230/240V single phase AC synchronous motor (Standard)
ii) A 24V DC motor (By Request)
iii) A 24V DC Stepper motor (By Request)

The motor is coupled to the main rotation shaft by a gear box. The drive system for types (i) and (ii) motors are operated by relays(not supplied) that are closed by the customers control circuitry across the increase or decrease contacts. Type (iii) motors are driven directly by the customers control circuitry.

The drive system is fitted with maximum and minimum end stop micro-switches to stop the motor at the limits of the brush arm travel

	Download CMV E Safety Instructions

	Download CMV F Safety Instructions