MK Diamond Baldor Motor - Manual (Page 28)

3-6 Maintenance & Troubleshooting MN408
Suggested bearing and winding RTD setting guidelines for Non−Hazardous Locations ONLY
Most large frame AC Baldor motors with a 1.15 service factor are designed to operate below a Class B
(80 ºC) temperature rise at rated load and are built with a Class H winding insulation system. Based on this
low temperature rise, RTD (Resistance Temperature Detectors) settings for Class B rise should be used as a
starting point. Some motors with 1.0 service factor have Class F temperature rise.
The following tables show the suggested alarm and trip settings for RTDs. Proper bearing and winding RTD
alarm and trip settings should be selected based on these tables unless otherwise specified for specific
applications.
If the driven load is found to operate well below the initial temperature settings under normal conditions, the
alarm and trip settings may be reduced so that an abnormal machine load will be identified.
The temperature limits are based on the installation of the winding RTDs imbedded in the winding as specified
by NEMA. Bearing RTDs should be installed so they are in contact with the outer race on ball or roller bearings
or in direct contact with the sleeve bearing shell.
Table 3-7 Winding RTDs − Temperature Limit In ºC (40 ºC Maximum Ambient)
Motor Load
(Typical Design)
Class B Temp Rise
< 80 ºC
Class F Temp Rise
< 105 ºC
Class H Temp Rise
< 125 ºC
Alarm Trip Alarm Trip Alarm Trip
< Rated Load 130 140 155 165 175 185
Rated Load to 1.15 S.F. 140 150 160 165 180 185
Note: • Winding RTDs are factory production installed, not from Mod−Express.
When Class H temperatures are used, consider bearing temperatures and relubrication requirements.
Table 3-8 Bearing RTDs − Temperature Limit In oC (40 ºC Maximum Ambient)
Bearing Type Oil or
Grease
Anti−Friction Sleeve
Alarm Trip Alarm Trip
Standard* 95 100 85 95
High Temperature** 110 115 105 110
Notes: * Bearing temperature limits are for standard design motors operating at Class B temperature rise.
** High temperature lubricants include some special synthetic oils and greases.
Greases that may be substituted that are compatible with Polyrex EM (but considered as “standard” lubricants
include the following:
− Texaco Polystar
− Rykon Premium #2 − Chevron SRI #2
− Mobilith SHC−100 − Pennzoil Pennzlube EM−2 − Chevron Black Pearl
− Darmex 707 − Darmex 711 − Petro−Canada Peerless LLG
See the motor nameplate for replacement grease or oil recommendation.
Contact Baldor application engineering for special lubricants or further clarifications.