1. EEM
PRESENTATION
ON
INDUCTION TYPE ENERGY METER
PRESENTED BY -

2. Introduction -
(Single Phase Induction Meter)

3. Construction -
 Driving system,
 Moving system,
 Braking syatem, and
 Registering system

4. Theory & Operation -
(Working)

5. (Phasor Diagram of Single Phase Induction Type Energy Meter)

6. Let ,
V = applied voltage
I = load current
ϕ = phase angle of load
IP = pressure coil current
Δ = phase angle between supply voltage and pressure coil flux
f = frequency
Z = impedence of eddy current paths
α = phase angle of eddy current paths
Eep = eddy emf induced by flux Φp
Iep = eddy current due to flux Φp
Ees = eddy emf induced by flux Φs
Ies = eddy current due to flux Φs
Net driving torque,
Td ∝ Φp Φs (f/Z) sinβ cosα
Td = K1 Φp Φs (f/Z) sinβ cosα
Where ,k1 = a constant,
β = phase angle between fluxes Φp and Φs ,
Φs = (Δ- ϕ)

7. • Thus , Driving Torque , Td = K1 Φp Φs (f/Z) sin(Δ- ϕ) cosα
• But Φp ∝ V and Φs ∝ I,
• ∴ Td = K2 V I (f/Z) sin(Δ- ϕ) cosα
• For constants f , Z and α ,
• Td = K3 V I sin(Δ- ϕ)
• If N is the steady speed, braking torque
• Tb = K 4 N
• At steady speed , driving torque = braking torque,
• ∴ K3 V I sin(Δ- ϕ) = K4 N
Thus, N = K V I sin(Δ- ϕ) and
for Δ = 90°
i.e., N = K V I sin(90°- ϕ)

8. • N = K V I cos ϕ
• Now V I cos ϕ = P (Power)
• Or N = K x (Power)
Total number of revolutions = ∫ N dt = K x ∫ (Power) dt = K x (energy)

9. Errors -
 Incorrect magnitude of fluxes,
 Incorrect phase angles,
 Changes in strength of brake magnet,
 Changes in disc resistance,
 Abnormal friction of moving parts
Adjustments -
 Preliminary light load adjustment,
 Light load adjustment,
 Creep adjustment