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Member Since 24 Apr 2002
Offline Last Active Today, 07:53 AM

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In Topic: Cscape 9.90 Released

03 August 2020 - 12:11 AM

Horner have released the much publicised CScape 9.9 SP3
This service pack is primarily aimed at the Advanced Relay logic programming environment with enhancements such as UDFBs, Gmail support for emails, downloadable protocol enable/disable, DHCP and DNS support, MQTT Sparkplug IOT support.
Some of these additional functions will require a firmware update which is also available for all processors.
Should you upgrade?
If you have a program that works and does not reuire the additional enhancements, then leave it alone.
If you are starting a new project and the enhancements are of value to you, or if you are using one of the newer processors, then you should upgrade.
NOTE: while Horner endeavour to keep as much upwards compatbility as possible, there can be changes in some established functions in new versions of CScape that may require tweaks in the code. Avoid upgrading the CScape version of code that is running in the field without fully testing it first.
You can have multiple copies of CScape on a single machine provided that they are installed in their own directory.

In Topic: Think About Energy Saving For Fix Speed Application

18 February 2020 - 05:26 AM

Adding a VFD (Variable Frequency Drive) to a motor running at a fixed speed and continuing to run the motor at that speed, does not make the motor efficiency improve except where:

The motor is very underloaded and a reduction in voltage will reduce the flux in the iron and thereby reduce the iron losses in the motor, BUT

  1. The reduction in voltage applied to the motor will :
    1. reduce the magnetising current
    2. reduce the flux in the iron and therebye reduce the inductive current flowing in the motor
    3. Increase the slip in the motor, thereby increasing the slip losses
    4. increase the work component of the current flowing in the motor
  2. Reducing the flux in the stator can result in an element of energy saving  BUT
    1. Reduced Flux ==> reduced Iron loss
    2. Reduced Flux ==> increase slip loss
    3. Reduced Flux with an open shaft motor ==> reduced line current and reduced copper loss
    4. Reduced Flux in the motor with load current equal to or greater than the magnetising current of the motor ==> increased motor current and increased copper loss.
  3. At line speed, the potential to save energy by using a VFD is limited by the true losses due to the use of an induction motor. With many modern machines, the efficiency is is typically quite high and until the load is very low and the actual iron loss is commonly less than a few percent of the full load of the induction motor.
  4. The iron loss is independent of the load, but there will only be a net gain when the load is very low, BUT the addition of a VFD to control the motor can reduce the iron loss by a small amount, but there is an immediate loss of two to three percent due to the the additional losses inherent in the additional losses in the from the use of a VFD.