We use universal motors in mixer grinders. Universal motors can run both on a.c. and d.c.
The universal motor works on the same principle that DC series motor works. DC series motor has the characteristics of operating at high-speed when there is no load and operating at low-speed when the load is applied. It has high starting torque characteristics.
So it is used in mixers, where initially we put some load at starting.
Apparent Power (S): It is defined as the product of r.m.s value of voltage (V) and current (1). It is denoted by S.
S = V/I Volt Ampere
A practical parallel resonance circuit is represented by an inductance and a resistance id one branch and a capacitance in other branches.
At resonance in a practical parallel resonance circuit, the impedance is maximum. Hence, it is called a rejector circuit, and it exhibits the property of voltage magnification.
Z = L/CR
The difference in level between points of supports and the lowest point on the conductor is called sag.
When the conductor is suspended between two supports at some level, it takes the shape of a catenary. However, if the sag is very small compared with the span, then the sag-span curve is like a parabola.
The tension at any point on the conductor acts tangentially. Thus tension To at the lowest point O acts horizontally.