Capacitors and uF values...

[Ladders]

Hi. I have taked out a Tesla capacitor control box from a lake, it had totally melted! The control panel is underated for the pump it controls.
Anyway I can get the correct rating control box but the capacitor uF value is different. The original one is 35uF and the new one would be 60uF.
Is that going to make any difference to the pond pump? Will it just make the start up even smoother?
Any constructive help appreciated. Thanks.

 

[MarkieSparkie]

The change could have been made to accommodate a wider range of pump motors. The larger capacitor will just provide a slightly larger phase shift to the start winding, in effect giving the same size motor a larger kick to get it started, this is unlikely to have any significant effect on the smoothness of the start-up.
However, the rule of thumb suggests a 35uF capacitor is required to start a 1.5Hp single phase motor, whereas a 60uF is required to start a 3Hp motor. Therefore I suggest that you check that you have the correct controller for your pump motor size, because although the motor will start OK with the larger capacitor the overload protection associated with that capacitor size is likely to be (double the current rating) for a larger motor and therefore if the pump became clogged or seized you would risk motor overload and burn-out before the cut-out operated.

 

[Ladders]

The change could have been made to accommodate a wider range of pump motors. The larger capacitor will just provide a slightly larger phase shift to the start winding, in effect giving the same size motor a larger kick to get it started, this is unlikely to have any significant effect on the smoothness of the start-up.
However, the rule of thumb suggests a 35uF capacitor is required to start a 1.5Hp single phase motor, whereas a 60uF is required to start a 3Hp motor. Therefore I suggest that you check that you have the correct controller for your pump motor size, because although the motor will start OK with the larger capacitor the overload protection associated with that capacitor size is likely to be (double the current rating) for a larger motor and therefore if the pump became clogged or seized you would risk motor overload and burn-out before the cut-out operated.

The pump is a Diver HF200M submersible pump 2.2kw 230v single phase...

 

[MarkieSparkie]

Hi Ladders, According to the Tesla design data book the Diver HF200M pump is nominally rated at 2Hp (1.5kW), requires a 35uF start capacitor and the thermal overload protection should be set at 10A. Their recommended pump controller is the Sintesi CBS 10/35, should you wish to replace the existing unit.

 

[Ladders]

Hi Ladders, According to the Tesla design data book the Diver HF200M pump is nominally rated at 2Hp (1.5kW), requires a 35uF start capacitor and the thermal overload protection should be set at 10A. Their recommended pump controller is the Sintesi CBS 10/35, should you wish to replace the existing unit.

How interesting. The info I stated is from the clients invoice when the pump was originally installed. It was 10 years ago though! Perhaps the rating was higher then 2.2kW? Thanks for the info.