Can a starting capacitor lower a fridge starting draw from 2400 watts to 800 or less without damaging the motor and how can the size of capacitor needed be determined?
could be If you lower the start cap size it may take milliseconds longer to start so it will still use the approximate same amt of power. Size? search for "appliance repair parts" enter your model number and you may be able to locate the value of the start cap. go from there.
28 people found this useful
by reversing the connection of the two windings
No, they only have a run capacitor that is permanently connected in series with the start winding.
Drawing block diagram of single phase capasitor start motor?
Types of Motors . There are different types of Capacitor-start motors designed and used in various fields. They are as follows: . Single-voltage, externally reversible type…, . Single-voltage, non-reversible type, . Single-voltage reversible and with thermostat type, . Single-voltage, non-reversible with magnetic switch type, . Two-voltage, non-reversible type, . Two-voltage, reversible type, . Single-voltage, three-lead reversible type, . Single-voltage, instantly-reversible type, . Two speed type, and . Two-speed with two-capacitor type. . These motors can be used for various purposes depending upon the need of the user. The starting, speed/torque characteristics of each of the above motors can be analyzed before employing them in work. .
I think the resistance value of starting winding is less than the running winding of the single phase motor
A capacitor fed winding on a single phase motor produces a phase shifted magnetic field that induces a starting torque in the rotor. Once sufficient RPM is achieved a centripe…tal switch disengages the start capacitor and, depending on design, switches in a run winding/capacitor, and running conditions are maintained from there. This is necessary as, without the extra winding, the induced current/magnetic field in the rotor would only be 180 degrees out of phase with respect to the field, and the rotor would not turn. Once the rotor is turning, a constant "slip" is maintained which keeps the rotor turning.
When a capacitor is so introduced, the voltage lags the current by some phase angle. In these motors, the necessary phase difference between the Is and Im is obtained by intro…ducing a capacitor in series with the starter winding. The capacitor used in these motors are of electrolytic type and usually visible as it is mounted outside the motor as a separate unit. During starting, as the capacitor is connected in series with the starter winding, the current through the starter winding Is leads the voltage V, which is applied across the circuit. But the current through the main winding Im, still lags the applied voltage V across the circuit. Thus more the difference between the Is and Im, better the resulting rotating magnetic field.
It should work okay as long as voltage rating is equal to or greater than the capacitor you are replacing.
The start winding needs a capacitor in series with it in order to produce a phase shifted magnetic field that will develop the torque necessary to bring the rotor up to operat…ing speed. Once operating speed it obtained, a centrifugal switch opens and disconnects the start winding - the rotor's inertia can then keep it going as needed.
Unless the motor is designed to be reversed, perhaps by changing some of the wiring, a capacitor start motor cannot be reversed. Consult the nameplate for specifics.
Most refrigerators use a single-phase induction motor which needs acapacitor to make it start running in the right direction.
Capacitors come in various sizes, your question is to non specific (capacitor for WHAT) for a detailed answer.
In order for an induction motor to run, a rotating magnetic field must be established. This requires the field windings to be supplied by currents that are out of phase with e…ach other. A capacitor is used to supply make the current through one field winding become out of phase (current leads voltage in a capacitive circuit) with the second.
As an electrician I can give you a vague answer with the information given. You need more specifics to do the calculations for the load amps and the supply voltage.. The par…ticular motor I looked at is a .6hp fan motor - 4.0 Amps @ 230V . (2650 x Full load amps ) divided by supply Voltage = MFD Example 2650 x 4amps = 10600 divided by 230volts = 46 MFD . But this is a general statement. The proper cap should be determined by researching the particular model you have. .