REFRIGERATION HVAC MECHANIC RED SEAL LICENSE EXAM REVIEWER - resistance of compressor motor windings

Watch this video in my YouTube channel 

Eternalson17

YouTube link

REFRIGERATION HVAC MECHANIC RED SEAL LICENSE EXAM REVIEWER - resistance of compressor motor windings

PROBLEM 

(from sample questions on): 

https://www.red-seal.ca/

When diagnosing the motor windings of a hermetic compressor, the following values are noted: 

Common-to-start: 

9 ohms 

Start-to-run: 

12 ohms 

What is the common-to-run value? 

Given

resistance of 

hermetic compressor windings

Common-to-start: 

9 ohms 

Start-to-run: 

12 ohms 

Unknown 

common-to-run value

SOLUTION 

common-to-run value

= Start-to-run value - Common-to-start value

= 12 - 9

=  3 ohms

*