The perfect match between an electric motor and VSD has finally been taken to the next level. WEG's massive R&D investment and the joint expertise of electric motor and VSD design engineers have addressed two of the major drawbacks of modern PWM drives: increase in motor temperature rise and fast transient high voltage peaks, the consequence of both being a dramatic reduction in motor life.

The new CFW11 WEG drives minimise voltage surges by carefully regulating the time between pulses of their IGBT transistors. This decreases the possible surge magnitude by 50%, allowing longer cable runs without the detrimental effects to motor insulation.

Flux-optimising technology (patented) decreases motor temperature rise by as much as 11%. *Since insulation life is doubled by every 10 degrees Celsius decrease in its operating temperature, this new WEG technology can increase motor life by as much as two-fold. A combination of low VPEAKS and dV/dt at the motor terminals, lower motor temperature rise, and high performance Drive and Motor architecture makes WEG the perfect solution to the most arduous industrial applications.

This new technology redefines the concept of a matched motor and drive package, with concrete benefits to users over and above the usual concept of matched packages.

Generally, when industry refers to a motordrive package they mean a motor and drive from the same supplier. This does not necessarily mean that the motor and drive are manufactured by the same supplier, nor does it provide any additional technical benefit. In fact if there is a problem, responsibility of rectification may be shifted from one supplier to another.

WEG’s R & D department have been studying the effects of PWM drives on AC electric motors for years, which has resulted in WEG incorporating the most advanced technology into their products.

There are today only a few suppliers of special wire for inverter fed motors, which the industry has anointed as ‘Spike Resistant-Wire’.

Vector control technology permits the operation of standard induction motors at very low speeds for extended periods of time. However, operation below rated speed affects the cooling efficiency of the shaft-driven fan, which results in increased motor temperature rise. To overcome that limitation, engineers developed derating factors and forced cooling fan systems. A practical rule dictated either of the two had to be applied for operation at or below 40Hz.

With WEG’s new Optimal Flux Technology (patented) this requirement is now a thing of the past. Each CFW09 and CFW11 (VECTRUE Inverter) has the electromagnetic circuit model of the WEG MEPS compliant motor built in. By carefully optimising the V/F ratios whilst the inverter is operating, the current (and therefore the motor heating) can be precisely controlled. The end result is a motor and drive package which must be regarded as a truly integrated solution to a long standing and expensive problem.

When a CFW09 and CFW11 inverter is used in conjunction with the WEG MEPS compliant range of motors and the continuous operating speed is 10Hz or above there is NO requirement for external forced cooling. This represents an ‘Up Front’ cost saving to the end user. Since there is no cooling fan, this also means there is also no power or control infrastructure. Furthermore, the absence of a fan motor yields ongoing energy savings with respect to fan energy usage. This alone may represent a saving of hundreds of dollars per year.

This system is only valid for with the WEG MEPS compliant Motors and CFW09 and CFW11 Variable speed Drives.

Traditional DC injection braking provides limited breaking torque, hence extending deceleration time with a corresponding increase in process cycle times. This can be costly for production lines, where short cycle times increase productivity and consequently, the organisation’s revenue. WEG’s optimal breaking (patented) is capable of reducing breaking time by up to 30%, especially in smaller motors.

The Vector control technique allows separate control of the Motor Torque and Flux Currents. Optimal Braking is composed of two control blocks :

Optimal Braking dissipates the braking energy in the same motor which generates it, thereby eliminating the external braking resistor (in some applications) and also the IGBT on the DC bus.

Optimal Braking is used where there is a requirement for increased braking over the standard applications. In fact the Optimal braking system can provide 100% braking from 25Hz down.

Optimal Braking is not designed to be used in highly regenerative applications, ie; hoisting, slipways and incline conveyors.

The CFW09 & CFW11 incorporate a feature called ‘Oriented Start-up’.

This feature steps the use through the set-up procedure. Upon first power up or after a reset to factory default parameters, an automatic programming routine guides the operator through a sequence of steps designed for the accurate completion of the minimum number of parameters necessary for the perfect match between motor and drive.

For Example:

P400 = Motor Volts

P401 = Motor Current

P402 = Motor RPM

P403 = Motor Frequency

P404 = Motor kW

P406 = Ventilation Type

P408 = Auto Tuning Routine

For a fast, accurate motor/drive setup procedure.

Once the ‘Oriented Start-up’ and commissioning procedure has been completed the entire programme may then be stored in ‘Non– Volatile

Memory’ in the drive keypad. This allows the programme to be up/down loaded at any time, even to another drive of the same capacity. Two ‘User Files’ can be stored within the drives and can be ‘called up’ with a digital input at any time.

The Auto Tuning procedure is specific to the motor/drive combination and should be carried out whenever this combination is changed.

Having a world class product is one thing. Service, training and backup is quite another. WEG have implemented the following strategies to assist you, the user, in having total peace of mind.

WEG is an ISO9001 and ISO14000 certified company (by BVQI in England). WEG’s strict QA procedures mandate functional testing of 100% of control cards.In addition, all drives are load tested for 2 hours. These tests are a pass or failure test, and and are carried out on all WEG drives at no additional cost. Other tests, including witness tests, can be performed upon request.

Based on the aforementioned spike-resistant wire ratings, dV/dt filters are not required if the following drive operating conditions are met.

1 Maximum VPEAK at the motor terminals: VPEAK = 1,500V

All WEG CFW09 and CFW11 Drives are been engineered to meet the above operating conditions at the inverter terminals. Likewise all WEG motors have been designed to withstand high levels of dV/dt and VPEAK.

The end result is a motor and drive solution which has been truly engineered to withstand the most difficult of operating conditions.

Additional to the individual benefits of WEG motors and WEG drives, when used together the following advantages are enjoyed: