Sequence of Electrical Tests

Component When Conducted Test
(underlines = links to test description)
Commutator, rebuilt Preinstallation (receipt from manufacturer) • ac high potential to ground (3500V)
• ac bar-to-bar (250V)
Postinstallation • ac high potential to ground (3500V)
• ac bar-to-bar (250V)
AC Stator,
AC Fields,
Exciter Rotor,
Exciter Fields		 Before and after interconnecting coils, prior to varnish treatment • Insulation resistance
• dc resistance
• Surge comparison
• dc high potential
After varnish treatments
(final acceptance tests)		 • Insulation resistance
• dc resistance
• Surge comparison (except ac fields)
• ac high potential
• Insulation resistance
DC Armatures After winding (before connecting coils to risers)
 • Insulation resistance
• dc resistance
• Surge comparison
• dc high potential
After connecting coils to risers but before any varnish treatments • Insulation resistance
• dc resistance
• dc bar-to-bar
• Surge comparison
• dc high potential
After varnish treatments (final acceptance tests) • Insulation resistance
• dc resistance
• dc bar-to-bar
• Surge comparison
• ac high potential
• Insulation resistance
NOTE:  For reconditioned components, the tests are run after cleaning and drying but before varnishing and again after varnishing. The test values for dc and ac high-potential and surge testing are 2/3 of the values used on rewound equipment.

Source: S9086-KC-STM-010/CH-300 Series, Naval Ships' Technical Manual, Chapter 300