Resistance Tolerance

Coil resistance tolerances are generally ±5% for heavier gage wires where precision coil windings are used and ±10% for finer gage wire where random winding processes are used. Tolerances are shown for each solenoid in the individual specification charts.

Residual Magnetism

The magnetism which remains in effect on a piece of magnetic material or between two pieces of magnetic material after the electromagnetic field created by the coil has been removed. An air gap is usually maintained between two magnetic poles to minimize the effects of residual magnetism.

Relative Permeability

The ratio of the flux density in a given medium to that which would be produced in a vacuum with the same magnetizing force. Non-magnetic materials, including air, have a relative permeability of 1, while magnetic materials such as iron, have initial relative permeabilities of approximately 2,000.

Random Wound Coil

A coil whose turns are allowed to wind randomly in no specific pattern. One turn may overlap another or may lay side by side or even spiral completely across the surface of the coil. Normally carries a ±10% tolerance on resistance.