Inspection method for Armature and Field Coils

1. Procedure For Armature & Field
Coil Inspection
Prepared By:
Abhishek Kr. Gautam
Executive-QA-Power Tools

2. Armature Testing

3. Test 1
Growler Machine Test:
Purpose: To check Insulation of armature

4. Step1: Put the Armature on Growler machine
as shown in figure below:
Step2: Switch On the Growler machine and
place a Metal Strip on each stack tooth as
shown below:
To check:
1.We have to rotate the armature and put the metal strip to each one of the stack tooth to
check whether metal strip magnetically stick to any one of the Stack tooth or not.
Result:
If the metal strip sticks to anyone of the stack tooth , then the insulation of armature is
damaged and hence we cannot use it.

5. Test 2
Multimeter Test:
Purpose: To check Continuity and Balancing of Armature

6. Step1: Switch On the multimeter and put 2
Multimeter Pins at Commutator bars which
are at 180º opposite to each other.
Step2: Repeat step 1 for each equally
opposite pairs of Commutator bars.
To check:
The readings for all Commutator bar Pairs should be exactly same. Example 2.2 mA for all
pairs.
Result:
If the reading for all Commutator bar pair is same then Armature is Ok in terms of
Continuity and Balancing.

7. Step3: Switch On the multimeter and put one Multimeter Pin on Commutator bar and another
one on stack tooth as shown below.
To check:
Response of Multimeter to detect any Insulation Damage.
Result:
If during this test there is no response from multimeter then we can conclude that
Insulation of armature is Ok. Hence we can use the armature.

8. Conclusion
It Is mandatory for all armatures to pass following
test i.e.
1.Growler Machine Test.
2.Multimeter Test .
3.Aesthetics i.e. no damage, no Rust etc.

9. Field Coil Testing

10. Test 1
Multimeter Test:
Purpose: To check Continuity and Insulation

11. Step1: Switch On the multimeter and put 1
Multimeter Pins at INLET wire and Other one
at OUTLET wire of same side as shown below.
Step2: Repeat step 1 for other set of INLET &
OUTLET wire.
Same Side Inlet and
Outlet Connection
Other set of Inlet and
Outlet Connection
To check:
Reading on Multimeter should be same for Both set of INLET & OUTLET Connection.
Result:
If the reading On multimeter for both set of INLET & OUTLET connection is same then
Field Coil is Ok in terms of Continuity and Balancing. Hence we can use the Field Coil.
For Example: In the above image there is difference in reading for both set of INLET &
OUTLET connection so the Field coil is Not Ok.

12. Step3: Switch On the multimeter and put one Multimeter Pin on Field Coil stack and another
one on Outlet/Inlet wire as shown below.
To check:
Response of Multimeter to detect any Insulation Damage.
Result:
If during this test there is no response from multimeter then we can conclude that
Insulation of Field Coil is Ok. Hence we can use the armature.

13. Conclusion
It Is mandatory for all Field Coil to pass following test
i.e.
1.Multimeter Test for Continuity and Insulation.
2.Aesthetics i.e. no damage, no Rust etc.

14. ThankYou