Energy Reduction: Electric Motors
Our primary technology for improving the performance of electric motors is 'Powerboss'
– a range of variable torque drives from 3 hp to 1600 hp which lower
motor operating temperatures and reduce energy consumption.
THE PROBLEM:
AC motors including 'premium efficiency' motors are only efficient at, or close to full-load, but many motors
are over-sized and typically operate well below full-load. For example,
a motor operating below 50% of load can still draw 80-90% of its
full-load power draw. This wasted energy takes the form of heat, noise and vibration - all of which reduce motor life and increase maintenance problems.
SOLUTIONS: Typically, engineers and maintenance staff use one or more of 4 possible solutions, all of which are designed to match the energy consumption of the motor more closely to its load. Note: when a motor is at full load, it needs all the energy it can get, so control systems need to be able to react very quickly (in milliseconds) to increases in load.
- Motor Replacement. If the motor is old, it may have been built at a time when energy was cheap and energy efficiency was not a priority. Older motors can usually be replaced with newer, more efficient ones, including 'premium efficiency' motors. A careful analysis needs to be made to calculate the payback on such replacements.
- Similarly, when energy efficiency was less important, motors were frequently over-sized, which caused them to operate at part-load for most of their lives.
- Variable Speed Drives are designed to reduce the speed of a motor to match lighter loads and reduce the power-draw, but they will only work if the application can tolerate changes in speed - known as "variable-speed, variable load applications". A good example would be a pump where the speed can be reduced if less fluid needs to be pumped. A bad application would be a hydraulic system where very rapid changes in load require fast changes in response time.
- A variable torque drive....
Powerboss,
the culmination of 10 years' R&D in the field of optimum motor
efficiency, uses the latest in micro-controller technology to monitor
the load requirements (torque) of a motor, and then control its
power-draw to exactly match that load 120 times a second.
Powerboss improves motor performance in 4 ways:
- A Soft-Start that is fully programmable and pays for itself over time
- Energy-savings whenever the motor load falls below 65% of full-load
- Cooler motor operation - typically more than 20 degrees cooler, which extends motor life and reduces maintenance & downtime
- Timed ‘switch-off’
provides 100% savings by switching equipment off if there is no
activity for a (user-adjustable) period, e.g. during lunch hours or
maintenance.
The
nearest comparable technology is a Variable Speed Drive (also called
Variable Frequency Drives or Voltage Inverters), which are designed to
change the speed of a motor to match varying loads. By contrast,
Powerboss is not used in variable speed applications, but is used in constant speed applications where the load is variable.