New Servopack YASKAWA Japan Electric 4.4KW 200-230vac 5.9hp SGDB-44ADG-P

 

 

 

 

 

Along with showing direction, the Xux plots also convey information about the intensity of the magnetic Weld. To achieve this, we introduce the idea that between every pair of Xux lines (and for a given depth into the paper) there is a same ‘quantity’ of magnetic Xux. Some people have no
diYculty with such a concept, while others Wnd that the notion of quanti4
Electric Motors and Drives fying something so abstract represents a serious intellectual challenge. But
whether the approach seems obvious or not, there is no denying of the practical utility of quantifying the mysterious stuV we call magnetic Xux, and it leads us next to the very important idea of magnetic Xux density (B).
When the Xux lines are close together, the ‘tube’ of Xux is squashed into a smaller space, whereas when the lines are further apart the same tube of Xux has more breathing space. The Xux density (B) is simply
the Xux in the ‘tube’ (F) divided by the cross sectional area (A) of the tube, i.e. B ¼ F A (1:1)
The Xux density is a vector quantity, and is therefore often written in bold type: its magnitude is given by equation (1.1), and its direction is that of the prevailing Xux lines at each point. Near the top of the magnet in Figure 1.2, for example, the Xux density will be large (because the Xux
is squashed into a small area), and pointing upwards, whereas on the equator and far out from the body of the magnet the Xux density will be small and directed downwards.
It will be seen later that in order to create high Xux densities in motors, the Xux spends most of its life inside well-deWned ‘magnetic circuits’ made of iron or steel, within which the Xux lines spread out uniformly to
take full advantage of the available area. In the case shown in Figure 1.3, for example, the cross-sectional area at bb’ is twice that at aa’, but the Xux is constant so the Xux density at bb’ is half that at aa’.

 

 

 

An ASD can reduce system maintenance requirements for  both the control and drive train equipment compared to other types of variable speed control.
C The ASD can reduce the wear on belts, sheaves, gearboxes, and couplings in a system.
C Control valves can sometimes be a maintenance problem due to lining wear when throttling a material which is very caustic or extremely rough in nature.
C All of these are wear items and can add to the overall maintenance of the process control plant.
C The ASD does not cycle motors on and off, as commonly seen with certain processes. By eliminating the cycling of these motors, the variable frequency drive eliminates the amount of in-rush and the torque pulsations felt throughout the system.
Advantages - Bypass Capability
Many ASD systems make use of a bypass starter in parallel with the drive which allows the drive
to be easily bypassed when critical applications require a back-up control means.
C Other types of variable speed control are usually physically coupled between the motor and the load and must be uncoupled, repaired, and then re-coupled into the line-up when there is a failure.
C The ASD can be bypassed in a matter of seconds where other types of speed control may be down for hours or even weeks, while it is being repaired if there is not a spare control.
Advantages - Multi-Motor Control Some ASD's can control multiple motors from the same drive which can be an advantage over other types of variable speed control devices.

 

 

 

 

 

 

 

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