Normal Ohm And Megohm Values - Xylem Goulds CentriPro Series Service Manual

Normal Ohm and Megohm Values

(Insulation Resistance) Between All
Leads and Ground
Insulation resistance does not vary with rating. All
motors of all HP, voltage and phase rating have similar
values of insulation resistance.
Condition of Motor and Leads
A new motor (without drop cable).
A used motor which can be
reinstalled in the well.
New motor in the well
Motor in the well in good condition
Insulation damage, locate and repair
What it Means
1. If the ohm value is normal, the motor windings
are not grounded and the cable insulation is not
damaged.
2. If the ohm value is below normal, either the
windings are grounded or the cable insulation
is damaged. Check the cable at the well seal as
the insulation is sometimes damaged by being
pinched.
Ohms Megohm
Value Value
20,000,000
(or more)
10,000,000
(or more)
2,000,000
(or more) (or more)
500,000 –
2,000,000 0.5 – 2.0
Less than Less than
500,000
20.0
10.0
2.0
.50
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