/ STARTING UP 199 



The electrical connections should be carefully inspected by 

 men of known responsibility. Loose bolted contacts, oil switches 

 with no oil, or insufficient oil in the pots, dinner pails stored on 

 top of the oil pots, or in the bus compartment are common sources 

 of troubles. 



After the machines are ready for operation the switchboard 

 instruments must be looked over and any necessary changes made 

 in the wiring. The synchronizing devices must be checked very 

 carefully. The majority of them are single phase and it often 

 happens that mistakes in connections cause incorrect indication 

 on the meter. Different phases on the two machines may be con- 

 nected to the synchronism indicator or the phase rotation of the 

 two machines may be different. The phase rotation must be 

 checked either by potential transformers and lamps connected 

 across a machine switch on all three phases at once, or a small 

 induction motor may be run in turn on all the generators. When 

 a motor is available to check the phase rotation, the synchronism 

 indicator can be checked single phase with a potential transformer 

 and lamps. 



Drying Out. Exciters and generators will need more or less 

 drying out, depending on the amount of moisture they have 

 absorbed. It is assumed that they have been protected from rain 

 and leaking water from concrete forms. The only other way 

 moisture can get into the machines is by sweating or condensa- 

 tion, due to the machines being colder than the surrounding air. 

 This condition can be largely, if not altogether, avoided, by keeping 

 the power-house at an even temperature. Where heating the 

 whole building is impossible, and the humidity is high, the machines 

 may be enclosed in a temporary shelter with steam or electric 

 radiators. In winter weather the machines should be kept above 

 the freezing-point. In most cases it is, however, impossible to 

 prevent some condensation and some drying is usually necessary. 



The exciters should, of course, have the first attention. If 

 possible they should be started up and run for several days with- 

 out 'field. The windage will then assist materially in drying and a 

 plumber's torch or stove can be placed under the commutator. 

 Care should be used, however, to prevent overheating. The 

 temperature should not get higher than 60 C. 



Where it is impossible to operate the exciter for any length 

 of time before starting, the preliminary drying can be accom- 



