Dennis Bogh of IEM, a division of IPS

Motor Fundamentals:

Abstract: Abstract: Tuesday – Electrical Motor Maintenance Testing - Low voltage (480 & 600V, Medium Voltage 2300V and up). AC machines electrical review with DC being only peripherally (vibration and most bearing issues are not covered). 
Subject matter covered:  
•    What tests and how often?
•    Why do we want to test?  
•    Management & maintenance styles
•    Environment and enclosures
•    Size & variety in fleet as well as age of machines
•    Spares and Urgency of downtime
•    Failures – predicted / not
•    Visual examination, sounds, smells (look at grounding brush)
•    Environment – temperature and humidity
•    Insulation Resistance
     o    How hard does it have to be?   On-line / Off-line
     o    Voltage test levels and acceptance criteria
     o    Temperature correction  
•    Space heaters     
•    DA and PI
•    Stepped DC 
•    Low frequence AC
•    AC high pot
•    Surge test (Baker)
•    Impedance test (PDMA)
•    Winding resistance (stator & field)
•    Capacitance
•    Partial Discharge On-Line
•    Acceleration time & current
                              
Wednesday – Review of all the basics.  This is exercise, be ready to work, there will be problems to solve!  
The little bit of arithmetic that I think you should know -Memory
•    DC
     o    Ohm’s law
     o    Shunts
     o    Resistor networks
•    Single phase
     o    Current, Power real and imaginary   Power factor
     o    Capacitance & Inductance    
     o    Measuring CT, PT, shunt
•    Three phase
     o    Current, Power real and imaginary   Power factor
     o    Capacitance & Inductance (lead/lag)
     o    Induction motor readings (nominal PF)
     o    Synchronous motor readings (general operation)
     o    CT & PT circuits used for measurement
     o    Expected accuracy
Testing components 
It is interesting and instructive to manually test these components.  Please bring your VOM.    I will bring a handful of capacitors, inductors, resistors, some SCR’s and diodes to test.   
•    Resistor (how accurate is accurate?   temperature)
•    Capacitor Impedance and capacitance
•    Inductor Impedance and inductance
•    Diode   Voltage drop and reverse breakdown
•    SCR    Switching & breakdown

Biography:

Biography - Dennis Bogh

Dennis Bogh (M’73, SM90, LM22) has a BS in Electrical Engineering from the University of Washington in Seattle.  He was employed by General Electric for 39 ½ years in various capacities including field engineering, management, and sales.  Since 2015, he has consulted for his own company, Bogh Consulting.  He is currently employed by IEM, a division of IPS, as a senior consulting engineer.   He participates as a member of the API 541, API 546, API 547, and IEEE 841 committees.  He is a registered Professional Engineer in the State of Washington.  

Address:Seattle, Washington, United States