Care of Motor-Generator Set
A. Machine will not build up or generate. This may be due to:
Machine rotating in wrong direction.
Brushes not making good contact. Clean commutator with fine sandpaper.
Wrong connections of field rheostat-check connections with diagram.
Open circuit in field rheostat. See if machine will build up with field rheostat cut out.
B. Excessive heating of the commutator. This may be due to:
Overload — Check your load and compare it with nameplate reading. Add the total amperes on all the panels and see that it does not exceed the ampere reading on the nameplate.
Wrong setting of the brush rocker arm. This causes sparking, which soon will cause excessive heating.
Rough commutator. This will cause the brushes to chatter, be noisy and spark. Caused many times by allowing copper to accumulate on the bottom of the brushes.
Insufficient pressure on brushes, resulting in sparking. This may be due to brushes wearing down to the point where the brush lead screw rests on the brush holder.
Dirt and grease accumulating between the brush and brush holder causing brush to stick;brush must always move freely in the holder.
Brush holder may have come loose, causing it to slip back, relieving brush press-Lire.
Brush spring may have become loosened, releasing the tension.
Watch commutator carefully and keep it in the best of condition. There will not be excessive heating without sparking. Excessive sparking may raise the temperature so high as to cause throwing of solder. You can avoid all this by taking proper care of the commutator.
C. Ammeters on Panels Read Reverse: This is caused by improperly connecting up batteries, which has reversed the polarity of the generator. This generally does no harm, since in most cases the batteries will automatically reverse the polarity of the generator. Generally the condition may be remedied by stopping the machine, reversing the batteries and starting the machine again. If this is unsuccessful raise the brushes on the machine. Connect five or six batteries in series in the correct way to one panel, while the machine is not in operation. Turn on the panel switch. When the machine is started, it will then build up in the right direction. If it does not do so, repeat the above, using a larger number of batteries.
D. Machine Refuses to Start. If there is a humming noise when you try to start the motor, and the outfit does not start, one of the fuses needs replacing. The outfit will hum only on two or three phase current. Never leave the power turned on with any of the fuses out.