Fluke 43B Application Guide

Motor Loads
Induction Motors
4
41
5
Calculate the current imbalance. Use the same formula as in the
previous section but substitute current for voltage.
Current imbalance for three-phase motors should not exceed 10%.
Example
a
33 A
1
+ 29 A
2
+ 34 A
3
= 96 A
TOTAL
= 32 A
AVERAGE
3
b
33 A
1
- 32 A
AVERAGE
= 1 A
29 A
2
- 32 A
AVERAGE
= - 3 A Largest value: 3 A
DEVIATION
34 A
3
- 32 A
AVERAGE
= 2 A
c
3 A
DEVIATION
x 100% = 9.4 %
32 A
AVERAGE
Note
To detect single phasing, always check the current on all three
phases. When a voltage measurement is made at the motor
terminals, the voltages will read close to normal as motor action is
inducing voltage into the open winding.

Fluke 43B Specifications

General

Category	Power Quality Analyzer
Interface	RS-232
Volts AC/DC	Yes
Ohms	Yes
Continuity	Yes
Diode Test	Yes
Capacitance	Yes
Harmonics Measurement	Up to 51st harmonic
Display	LCD
Battery Life	Approximately 6 hours
Weight	1.1 kg (2.4 lb)
Data Storage	Yes
Amps AC/DC	0.1 to 1000 A (with clamp)
Power Measurement	W, VA, VAR, PF
Dimensions	50 mm
Current Measurement Range	Via current clamp accessories (not built-in)