Baker D30R User Manual - page 74
Troubleshooting
12/3/2009 | 71-022 V6
D30R
74
Applications: What to do first!
Review the section below on Common Application Problems. Please have Basic Information
about the tester and specific information about the motor being tested should be available
when calling or faxing to assist Baker Instrument Company, an SKF Group Company
personnel in determining a solution to the problem.
Examples:
Hp
rating
kW
rating
RPM
rating
Operating voltage & current
How the item being tested is wound and/or number and type of coils
Application of motor/generator
In short, any information that can be provided from the motor nameplate is helpful. A great
tool is a printout or sketch of the waveforms displayed on the tester. If a FAX is available,
send a draft to 970-282-1010, attn: Applications.
Common application problems
Following are the common application-related problems. Please review the following cases.
1)
The surge tester will not give the desired output test voltage or the apparatus under test.
The Test motor may be too large for the instrument being used. The impedance of the
windings may be too low.
The Digital tester may be at fault in this case.
Do not
continue testing until contacting Baker
Instrument Company, an SKF Group Company Applications Department.
2)
Separation of compared wave patterns is seen when surge testing on coils that are
assumed to be good, even on brand new motors or windings. Often, separation is seen in
all three comparisons for three phase motors, but to varying degrees. There may not be
separation throughout the whole wave pattern.
This situation can be seen in DC fields or rotating poles. Be sure the coils being compared are
being tested in identical configurations; i.e. both coils are wound clockwise beginning to end.
On very large equipment, slight differences in capacitance to ground may be the cause. At low
voltage levels, begin the test again with the black GRD lead removed from the motor frame. If
the separation is now gone, capacitance to ground was effecting the test.
3)
There is no dampened sinusoidal wave pattern on the display when testing a coil. The
wave pattern rises on the left and then slowly drops as it trails off to the right of the
screen. It may or may not cross the zero/base line.
The coil under test is probably too high of an impedance to get a good working pattern. The
coil may be very high in resistance and turn counts. The inability to surge test this coil, or
group of coils in series, will remain unless they can be broken down to smaller units of lower
impedance.
A broken test lead may be the cause. Under heavy use, test leads should be checked weekly
to ensure that there is no breakage. Grasp the boot and clip in one hand while pulling on the
lead with the other hand. A broken lead will stretch, whereas a good lead will not.
4)
The instrument has the “Open Ground” light lit.