How much resistance should a relay coil have?
How much resistance should a relay coil have?
The electrical resistance (impedance) of the coil is vary and is different depending upon the manufacturer of the relay as well as relay’s type, but in general a typical value should be expected between 50 ohms and 200 ohms.
What are 3 types of start relays?
Several types of starting relays are used to assist in the starting of single-phase compressors. These include the current relay, potential relay, and PTC (positive temperature coefficient) relay. Each performs the same function but in a different manner.
What do you need to troubleshoot a starting relay?
A simple ohmmeter is all that is needed to troubleshoot a current starting relay. After taking the connecting wires off of the relay and disconnecting it from the motor, measure the resistance across the relay coil between L and M. Since this relay coil wire is a very short and fat wire, its resistance will be very low (usually less than 1 ohm).
Why is the potential relay not being used?
For example, if the ohmmeter reads 200 ohms, the potential relay should still be discarded because of dirty or pitted contacts. Open contacts between terminals 1 and 2 will prevent the start capacitor from being in the circuit. The start capacitor is a high microfarad capacitor, which is in series with the start winding. (See Figure 2.)
What kind of motor does a starting relay use?
This configuration makes the motor a permanent split capacitance (PSC) motor only while running. A simple ohmmeter is all that is needed to troubleshoot a current starting relay. After taking the connecting wires off of the relay and disconnecting it from the motor, measure the resistance across the relay coil between L and M.
What happens when the Ohm of a relay is infinity?
If the ohm reads infinity on the (R x 100) scale, the relay coil is opened. The relay should be discarded and a new one installed. An opened relay coil will prevent the contacts between 1 and 2 from opening. This is caused from no magnetism in the iron core that the coil is wrapped around. This, again, will cause high amp draws.
What do I need to troubleshoot a potential relay?
One Comment. A simple ohmmeter is all that is needed to troubleshoot a potential relay. After taking all of the connecting wires off of the potential relay, measure the resistance across the 1 and 2 terminals. The resistance should read close to zero, since there are normally closed contacts between terminals 1 and 2.
If the ohm reads infinity on the (R x 100) scale, the relay coil is opened. The relay should be discarded and a new one installed. An opened relay coil will prevent the contacts between 1 and 2 from opening. This is caused from no magnetism in the iron core that the coil is wrapped around. This, again, will cause high amp draws.
What kind of amps are in a starting relay?
The amp draw would be somewhere between running load amps (RLA) and locked rotor amps (LRA). The motor’s protective device would soon open. A short-cycling situation would occur.
What should the resistance of a relay coil be?
The (R x 100) scale is a good one to use. The R x 1 scale can fool a technician into believing that there is an open coil because of the coil’s extremely high resistance. It is not uncommon to have the resistance read in many thousand ohms. If the ohm reads infinity on the (R x 100) scale, the relay coil is opened.
