Single-phase motors have a reduced starting torque due to their intrinsic design. Starting torque is around 30-40% of the nominal torque at full power output. When designing circuits where a single-phase motor must start under load, a proper calculation must be done followed by a field test to ensure proper starting. Alternatively, you can overcome the problem with the startup valve SUV.

The SUV Valve can be optionally installed in our central manifolds.  The valve is to be mounted in cavity 9 of U type and cavity 13 of S type central manifold.  This cavity is not machined by default but is easily machined with a drill press by drilling cavity 9 and threading it for 1/4 BSPT.  The function of this valve is to discharge the pressure inside the central manifold line between the pump and the check valve when the power pack is off. It is typically used with a single-phase motor starting under load, overcoming the inherent low torque at the start-up of single-phase AC induction motors