Gentlemen, Thanks for all the reponses, most interesting. I will discuss some of them with the company responsible for the total install.
I'll try to reply to as many questions as possible.
- Ambient: 43^C
- VFD Carrier frequency: 5Kz (per cust @ factory default)
- Motor nameplate FLA...
Application: Centrifugal Pump (Variable Torque)
Motor: 200HP 1200RPM (FL RPM = 1185) 3/60/575V
447T TEFC
Some history: Motor/Pump operated approx. 4 years without problems with Direct on Line starting and running at full load RPM. Routine motor maintenance and...
Utilizing Electronic Soft Starting and/or VFD will increase allowable number of stops/start.
NEMA is best for small motors.
Larger motors consult motor manufacturers.
All subject to load WK^.
Above the fundemental frquency - 50Hz - the motor looses torque proportionally. ie 50/100 - 0.5
(There comes a point of saturation where the motor will just die and loose any abilty to function)
If the pump is a Variable Torque pump the load increase HP(Cubed)and Torque(Squared).
Take a...
Motor Thermal Curves (Thermal Damage or Capability Curve)when supplied from motor manufacturers, normally include:
Thermal heating constant running: ie Time to reach thermal equalibrium.
Thermal cooling constant stopped: ie Time to cool from hot condition.
Consecutive start: ? Cold ...
Shortstub
Thanks for the clarification. Out of interest....Does this value relate to Divisions or Zones ? EU (ATEX) or North American.
I'm not clear on yr Space Heater comment. Our primary concern would be for surface temp and type of heater.
I believe yr alert to be well received...
What type of load: Constant Torque or Variable Torque ?
What is the operating speed range: ?Hz to ?hz
Are you getting hi current at all speeds ?
Is the VFD a regular V/Hz drive ?
What is the carrier frequency ?
What is the output voltage ?(use a true RMS meter)
Is this a new application or...
Division 2 Class I:
Where ignitable concentrations of flammable gases, vapours or liquids are not likely to exist under normal operating conditions.
Note: Only hazardous under ABNORMAL conditions.
---------------------------------------------------------
Occurance of all items taking place...