Product Overview  |  Technical Specifications  |  Applications 

THE CENTRALIZED MOTOR START UP COMPENSATION SYSTEM (CMSCS)
CMSCS can solve the electrical problem of voltage drop and high starting current much better than soft starters. The CMSCS does not address and cannot solve the mechanical problem of high initial torque that could potentially damage the motor.

 
SPECIFIC CMSCS APPLICATIONS
STANDALONE SOLUTION
In any case that a direct motor start is possible without the possibility of creating mechanical damage, CMSCS can be a very efficient and cost-effective solution. The CMSCS advantage is even greater in a location where there are many motors, since it is a central compensation solution. Whereas soft starters and VSD/VFD’s create harmonics and therefore power quality problems, the CMSCS helps to improve the power quality of the electrical network. A large portion of the motor starting applications do not have issues of potential mechanical damage caused by excessive starting torque.
 
COMBINATION SOLUTION
In cases that there is a need to reduce the starting torque as well, CMSCS is not used a standalone solution, but rather is combined with a soft starter to provide for the complete requirements of the motor:  
In areas with weak electrical networks, a soft starter may not reduce the voltage drop enough for the motor to start each time. In this case, a CMSCS can be used as a considerably less expensive substitute than a VSD/VFD if speed control is not necessary for a manufacturing process.
In cases that there are Power Quality problems during the motor start, CMSCS can improve the power quality

 
CMSCS - OVERVIEW MOTOR STARTING TECHNOLOGIES
This case study simulation analysis demonstrates the results of a 5MW motor supplied by a 11.5kV electrical network supported by a 15MVA transformer. The chart below highlights the following starting scenarios:

• Direct Online Connection
• Soft Starter
• 32MVAr CMSCS - Sized for Maximum 2.5% Voltage Drop
• 25MVAr CMSCS – Sized for Maximum 6.0% Voltage Drop
• Combination Soft Starter with 12MVAr CMSCS
• 12MVAr CMSCS – Sized for Maximum 10.0% Voltage Drop

 
SYSTEM COMPARISON
The table below describes the parameters and results from each possible solution. The graphical reference to each solution is at the bottom of each column.

CONCLUSIONS 

• The CMSCS does not increase the harmonic level for the voltage and the current (in most cases, the harmonics levels are improved).  
• The voltage drop caused by reactive energy demand could be completely eliminated using CMSCS, however due to cost considerations, a compromise should be considered.
• The startup period is minimized using the CMSCS solution, thus avoiding unnecessary wear to the motor and increasing the motor’s life expectancy.  
• The lowest levels of starting current occur when employing the CMSCS solution.
• During startup, the cleanest sinusoidal waveforms are achieved via use of the CMSCS solution.
• The complete cost of the CMSCS in Medium Voltage applications, including the additional transformer and protection accessories, is less expensive than a soft starter solution in many operating scenarios (especially when more than one motor is used).
  

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