Energy Efficiency Using VFD and IE2/IE3 Motor Vs. Starter and Standard Motor

Were the installation in the UK, then a combination of approved inverters and EFF1-rated motors would qualify for enhanced tax allowances, meaning that the whole of the installation would qualify for tax relief in the first year, making the installation highly tax-effective and thereby improve its payback time; it makes sense to do it here. For further information on tax-effective energy savings, see the Carbon Trust's website for starters.

Thanks for the Response & valuable information.

This solution is also applicable for UK customers. but what about the overall Capital (installation) cost of such solution in camparison to standard solution.

The capital cost will be higher, clearly, because of the inverter and the possibility of the larger frame size. Given that 20-40% of a country's electricity bill could be related to spinning motors, the installation-life-cycle cost, through using high-efficiency solutions, will be lower.

http://www.abb.co.uk/cawp/seitp202/c1256c290031524bc1256cf7003f391e.aspx

Sorry I don't agree with the larger frame size on vsd motors or eff1 (if I understand you correct). In SA the vsd motors and eff1 motors are in the same frame size and all our lv motors are imported from Europe, Brazil and China..

The only factor that will result in a "larger" frame on a motor driven by vsd is the load and the speed the motor has to deliver the torque (reducing the motor rpm). This may result in a larger motor (higher kW) needed to do the work, but the motor will still remain the same frame size for that specific kW.

For VFD application motor, the speed ratio is for eg. 1:10 i.e 150:1500 RPM, when the motor have to run at 1/10 th speed , more temperature rise will be there. Higher frame size will provide higher air space.Also, fan is provided on the shaft for cooling purpose.

- The System is rated at 100 % load, however, the motor is loaded up 70 % load, so we can optimised the VFD for 75-80% ( as VFD are direct torque controlled).

The amount of energy consumed by an AC motor has to do with 2 things: load and efficiency. So if a motor is only 70% loaded, it is ALREADY going to only pull 70% of the FLC. The losses in the motor will be better with the energy efficient motor design, but if the load is exactly the same in both cases, the VFD will serve only to decrease the throughput efficiency because the VFD adds its own losses. A VFD only saves energy if, in the process of reducing the speed, you reduce losses in the load. A classic example is in a pump system, where the load is normally varied by a throttling valve of some sort. That valve represents a pressure drop and therefore a loss in the load. Eliminating the valve and using a variable speed drive eliminates that loss in the system and saves energy. If there is no reduction in load losses, there is no energy savings with a VFD.

- So current reduction, less cable daimeter (Saving). -If Three pumps are connected to the bus then Bus bar size reduction, Switch fuse unit (SFU) reduction(saving) & overall transformer rating reduction(saving).

Very incorrect! No installation rules I am aware of allow you to down size conductors, be they cables or busbars, based upon actual connected current. they must be sized for the MAXIMUM current, assuming that at some point the motor MAY draw FLC. In fact, here in the US, you are REQUIRED to size the conductors based upon 125% of t VFD's MAX CURRENT RATING, with now allowances for actual load current. So if, for example you use a VFD that is larger than the motor (which is perfectly fine to do), you must still size all conductors as if the VFD were connected to a full load at it's maximum current rating.

JRaef..

Ur right.......VFD is no way related with EE motors.......

The puspose of VFD is reduceing in incresing the Speed of motor to control the pump flow......

EE motors construction itself reducing the losses......

i hope m correct its my practical exp...

Reg

Santhosh

Implement Demand Controlled Ventilation with the VFD and economizer and get an additional 10% energy efficiency.