Hayward TriStar VS 950 / Jacuzzi - JVS270S 2.7THP Pump questions - input voltage - current draw

[Bill1974]

I am installing the Jacuzzi and was looking at the data plate on the motor for voltage and FLA. At 230V the FLA is 10.2 and at 115V the FLA is 12.2. Normally the difference is close to 1 to 2 (at 230V the current is half of what it would be if the voltage is 115V). For anyone that has one of these, have you measure the amperage at the max load? If so what is it and what voltage are you running it at?

Is is possible that the VFD is limiting the power differently depending on the input voltage? For instance, at 230V the current draw is being limited to around 6.1A even thou the motor is capable of 10.2A? Maybe because the pump housing and impeller are not sized well for power the motor could supply. Or is the pump limited when it's powered by 115V? Hayward doesn't publish different flow curves based on input voltage.

My experience with VFD driven pumps is liquid ring and centrifugal vacuum pumps and single speed pumps. Unless the motor design and/or the VFD design is complete Crud the FLA's should not be so close. At 90% efficiency the watts at 230V is 2111 and at 115V it's 1263.

What am I missing?

 

[Bill1974]

I'll answer my own question. I found in the Hayward Sell sheet, the HP is 1.5HP when powered by 115V and 2.7HP on 230V. You would think this information would be in the manual and clearly stated on the motor label. The Jacuzzi literature doesn't mention anything.

I wonder what the flow curves are between 2400 and 3450 rpm at 115V. I'm guessing the flow curves are the same up to 2400 rpm (i wonder how much difference there is in watts between 230V and 115V).

Good that I figured this out and new know the pump needs 230V to achieve full power. The bad is now I need to drop some extra coin on a double pole GFCI breaker.

 

[1poolman1]

I am installing the Jacuzzi and was looking at the data plate on the motor for voltage and FLA. At 230V the FLA is 10.2 and at 115V the FLA is 12.2. Normally the difference is close to 1 to 2 (at 230V the current is half of what it would be if the voltage is 115V). For anyone that has one of these, have you measure the amperage at the max load? If so what is it and what voltage are you running it at?

Is is possible that the VFD is limiting the power differently depending on the input voltage? For instance, at 230V the current draw is being limited to around 6.1A even thou the motor is capable of 10.2A? Maybe because the pump housing and impeller are not sized well for power the motor could supply. Or is the pump limited when it's powered by 115V? Hayward doesn't publish different flow curves based on input voltage.

My experience with VFD driven pumps is liquid ring and centrifugal vacuum pumps and single speed pumps. Unless the motor design and/or the VFD design is complete Crud the FLA's should not be so close. At 90% efficiency the watts at 230V is 2111 and at 115V it's 1263.

What am I missing?

As you found, some VSP motors actually automatically lower their horsepower rating if the lower voltage is used. Found that out while reading some obscure line in a manual for a replacement motor, Nidec Neptune, I believe. Never tried using 120V on a VSP, so never paid attention to that plate and the horsepower reduction.

Flow curves are based on motor RPM and head, not input voltage. While input voltage may remain constant, amp draw may change as the "head" (work load) increases at that RPM due to a filter getting dirty, flow directed to a restrictive water feature or spa jets. The pump isn't going to slow down when that happens, but it will continue to work harder and try to move whatever amount of water that RPM/impeller combination are designed to move. It could be that the drive on a Hayward VSP will automatically limit the amp draw if it reaches its maximum.

Its not so apparent on a VSP, but on a single-speed pump you could hear the motor working harder at its full 3450-rated RPM and an amp meter would show the increase in current in those situations. We used to have to adjust old open-faced impeller pumps based on maximum load using a meter so as to not overload a motor. Proper pump installs were more work, but kinda' fun with those old pumps.