VFD and small pump

[weressl]

I turned off the feature that would, I believe, calculate and provide thermal protection for the motor based on the load type, current and motor speed. I set actual overcurrent parameter to motor FLA. No one was around so I will check in tomorrow and see how it works out

This is the problem commenting on posts:

You are making two contradictory statements above or at least one that is meaningless in context. There are several people who mentioned that the 5400rpm issue and it certainly still can be the issue if you set your max. frequency to anything but 60Hz base. There are specific parameters associated with each discussion point yet there is none mentioned. You may, or may not, make changes based on people's comment, but without referenceing specific parameters for a specific drive those can be erroneous and damaging too.

To sum it up these discussions can drift to dangerous areas where comments may be taken as advice, or even directions and can have detrimental effects.

 

[GeorgeB]

A 4 pole 60Hz motor will run 1800RPM minus slip%. If you programmed the motor parameters as 4 pole, the 5400RPM value should be meaningless as far as the VFD is concerned.

As far as the MOTOR is concerned, I don't agree with you; it would mean that I should limit frequency to 180 Hz. Now running the Viking PD pump at those speeds ... new pump time <g>. Of course, the "constant" pump pressure puts the load in constant torque mode ... operating the motor (and VFD) at speeds in excess of 60 Hz is USUALLY a constant power situation ... so if loaded, the system would not likely get there if the VFD overloads <REAL BIG GRIN> did their job ... where did this thread start, a 5HP VFD on a 1 HP motor ... "the plot thickens"

 

[ptonsparky]

Ok.

The 5hp vfd was used originally because they had one available. No other reason.

The 1hp vfd was installed because the the motor rated current needed to be within 30 - 120% of the drives rated current. The 5hp drive current was to high. My mistake for not remembering that detail. I paid for the correction.

I did not increase the max hz 20.07 setting for the drive. I have more than enough product at 9HZ. The motor may be able to run at 5400 rpm. I have no idea about the pump. Moot point with the 9 Hz product flow.

I called tech support back to make sure my understanding of parameter 70.07 was correct. I am close enough. The tech I spoke to indicated that the speed of the motor must be low for the OL1 fault to occur.

Disabling 70.07 does not disable the Motor Rated Current setting of 60.01 or 20.05. He did suggest that parameter 70.03 be reduced to 115 - 120%

 

[weressl]

Ok.

The 5hp vfd was used originally because they had one available. No other reason.

The 1hp vfd was installed because the the motor rated current needed to be within 30 - 120% of the drives rated current. The 5hp drive current was to high. My mistake for not remembering that detail. I paid for the correction.

I did not increase the max hz 20.07 setting for the drive. I have more than enough product at 9HZ. The motor may be able to run at 5400 rpm. I have no idea about the pump. Moot point with the 9 Hz product flow.

I called tech support back to make sure my understanding of parameter 70.07 was correct. I am close enough. The tech I spoke to indicated that the speed of the motor must be low for the OL1 fault to occur.

Disabling 70.07 does not disable the Motor Rated Current setting of 60.01 or 20.05. He did suggest that parameter 70.03 be reduced to 115 - 120%

Did you mention to the tech that this is a constant torque application?

As I mentioned before 9Hz is pretty low speed for a 60Hz rated motor, especially if it is a constant torque application. At that speed, even if you have shaft mounted cooling fan TEFC, the forced cooling is non-existent.

Overload protection for variable speed drives is an I2t mathematical formula biased by the frequency, which reduces the allowabe current at reduced frequencies. So that you have not changed the maximum current in para 20.05 is not meaningful in this context, you still have no overload protection - see above paragraph - if you set 70.07 to 02. In the tabular format of the parameters, it calls for to be set for 00 for constant torque applications(which you wanted and I agree) and 01 for VT.