1. L-9 MAGNETIC CIRCUITS

2. ELE 1001: Basic Electrical Technology
Objectives
To solve various kinds of problems involving parallel magnetic circuits.
Dept. of E&E, MIT, Manipal

3. Content Parallel magnetic circuit
ELE 1001: Basic Electrical Technology
Content
Parallel magnetic circuit
Dept. of E&E, MIT, Manipal

4. Parallel magnetic circuit
ELE 1001: Basic Electrical Technology
Parallel magnetic circuit
More than one path for flux.
Total flux Φ is split into Φ1 and Φ2 such that Φ = Φ1+ Φ1 A B C D E F Φ Φ1 N Φ2
Analogous electrical circuit
Dept. of E&E, MIT, Manipal

5. Parallel magnetic circuit with air gap
ELE 1001: Basic Electrical Technology
Parallel magnetic circuit with air gap Φ1 Φ2 A B C D E F Φ
Analogous electrical circuit
Dept. of E&E, MIT, Manipal

6. ELE 1001: Basic Electrical Technology
Exercise1
The core shown has a relative permeability of Find the current required for the exciting coil to produce a flux of 10 milliWb in the central limb. Take total number of turns of the coil as 500 turns.
Ans: A
Dept. of E&E, MIT, Manipal

7. ELE 1001: Basic Electrical Technology
Exercise2
A magnetic circuit made of silicon steel is as shown. The central limb has a cross sectional area of 800 mm2 and a coil of 500 turns. Each of the side limbs has an area of 500 mm2. Calculate the magnetizing current required to produce a flux of 1 mWb in the 1 mm air gap if μr=1000, length BE = 150 mm; length BAGIDE = length BCHJFE = 250 mm. Neglect leakage factor.
1mm
5mm A B C D E F G H I J
Ans: 2.04 A
Dept. of E&E, MIT, Manipal

8. Summary More than one path for flux in parallel magnetic circuit.
ELE 1001: Basic Electrical Technology
Summary
More than one path for flux in parallel magnetic circuit.
Total flux divides into the available parallel paths.
Dept. of E&E, MIT, Manipal