NEW ORIGINAL Yaskawa Servo Amplifier 3.96KW AC servo drives SGDB-44ADS

 

 

 

 

 

 

IntroductionThis Section describes the applicability of this User ManualThe E7 Drive is a Pulse Width Modulated Drive for AC induction motors. This type of Drive is also known as an AdjustableFrequency Drive, Variable Frequency Drive, AC Drive, AFD, ASD, VFD, and Inverter. In this manual, the E7 Drive will bereferred to as the "Drive".The E7 Drive is a variable torque AC drive, designed specifically for HVAC applications in building automation, includingfans, blowers and pumps. A new benchmark for size, cost, performance, benefits, and quality, the E7 includes numerousbuilt-in features such as network

communications, H/O/A, PI, and energy-savings functions.®The E7 has embedded communications for the popular building automation protocols, Johnson Controls MetasysandTM®®Siemens APOGEEFLN, as well as Modbus.

 

 

 

 

 

 

There are three different types of ASD's on the market that primarily differ in the type of rectification they use to convert AC to DC and back to AC.
C VVI - Variable Voltage Input
C CSI - Current Source Input
C PWM - Pulse Width Modulated
These drives take the AC input voltage and frequency, covert it to DC using rectifiers, then convert it back to AC in an invertor which changes the voltage and frequency.
Variable Voltage Input (VVI)
The VVI is the oldest AC drive technology and was the first AC drive to gain acceptance in the industrial market.
C The VVI is sometimes called a “six-step drive” due to the shape of the voltage waveform it sends to the motor.
C VVI drives are fairly economical between 25 and 150 horsepower for ranges of speed reduction from 15 to 100% (about 10 to 60 Hertz).
C These drives are also used widely on specialty high speed applications (400 to 3000 Hertz).

Advantages:
good speed range
multiple motor control from one unit
simple control regulator
Disadvantages:
Power Factor decreases with
decreasing speed
Poor ride through ability for low input
voltage
Generates significant output
harmonics
Low Speed Motor Cogging (shaft pulsing/jerky motion)
Requires Isolation Transformer on Input Side
During low speed operation (below 15-20 Hz) cogging can be a problem where the jerky motion of
the motor shaft can create problems for bearings, gears, or gear reducers.

 

 

 

 

where F is in newtons when B is in tesla, I in amperes, and l in metres. This is a delightfully simple formula, and it may come as a surprise to some readers that there are no constants of proportionality involved in
6 Electric Motors and Drives equation 1.2. The simplicity is not a coincidence, but stems from the fact
that the unit of current (the ampere) is actually deWned in terms of force.

 

Strictly, equation 1.2 only applies when the current is perpendicular to the Weld. If this condition is not met, the force on the conductor will be less; and in the extreme case where the current was in the same direction
as the Weld, the force would fall to zero. However, every sensible motor designer knows that to get the best out of the magnetic Weld it has to be perpendicular to the conductors, and so it is safe to assume in
the subsequent discussion that B and I are always perpendicular. In the remainder of this book, it will be assumed that the Xux density and current are mutually perpendicular, and this is why, although B is a
vector quantity (and would usually be denoted by bold type), we can drop the bold notation because the direction is implicit and we are only interested in the magnitude.

 

The reason for the very low force detected in the experiment with the bar magnet is revealed by equation 1.2. To obtain a high force, we must have a high Xux density, and a lot of current. The Xux density at the ends of a bar magnet is low, perhaps 0.1 tesla, so a wire carrying 1 amp will experience a force of only 0.1 N/m (approximately 100 gm wt). Since the Xux density will be conWned to perhaps 1 cm across the end face of the magnet, the total force on the wire will be only 1 gm. This would be barely detectable, and is too low to be of any use in a decent motor. So how is more force obtained?

 

The Wrst step is to obtain the highest possible Xux density. This is achieved by designing a ‘good’ magnetic circuit, and is discussed next. Secondly, as many conductors as possible must be packed in the space
where the magnetic Weld exists, and each conductor must carry as much current as it can without heating up to a dangerous temperature. In this way, impressive forces can be obtained from modestly sized devices, as anyone who has tried to stop an electric drill by grasping the chuck will testify.