
Maintenance & Troubleshooting 3-5
MN400
Suggested bearing and winding RTD setting guidelines
Most large frame AC Baldor motors with a 1.15 service factor are designed to operate below a Class B
(80
°
C) 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.
Winding RTDs
−
Temperature Limit In
5
C (40
5
C Maximum Ambient)
Motor Load
Class B Temp Rise
3
80
°
C
(Typical Design)
Class F Temp Rise
3
105
°
C
Class H Temp Rise
3
125
°
C
Alarm
Trip
Alarm
Trip
Alarm
Trip
3
Rated Load
130
140
155
165
175
185
Rated Load
to 1.15 S.F.
140
150
160
165
180
185
Note:
S
Winding RTDs are factory production installed, not from Mod
−
Express.
S
When Class H temperatures are used, consider bearing temperatures and relubrication requirements.
Bearing RTDs
−
Temperature Limit In
5
C (40
5
C 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
Note:
* 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.
Luggage Point STP ST18 Pre Treatment (Aqua-Screen (Andritz) Operation and Maintenance Manual) General
Q-Pulse Id: TMS579
Active: 13/12/2013
Page 185 of 316