Dynamotor Bearing Grease

[David Dunlop]

I have a question about grades of grease and their application to the bearings in a wireless set dynamotor.

The two Robbins & Meyers dynamotors used in the Supply Unit of the Wireless set No. 52 used ANDOK-C grease in their bearings. This was a sodium based, Grade 4 grease manufactured by Imperial Oil which has been discontinued for several decades with no direct replacement. This was a high temperature grease popular in high speed electric motors, particularly those mounted in a vertical orientation. The two dynamotors are mounted horizontally in the 52-Set, however.

Imperial/Mobil Oil currently make a lithium based, Grade 3 grease that is a close match in specs to ANDOK-C. This Grade 3 grease, however, is very hard to find in cartridge format in single cartridge amounts, and pricy as a result. This Mobil grease has a sister, Grade 2 equivalent that is readily available locally in single cartridges.

I am simply not familiar with the grading system for grease to know if a jump down from Grade 4 to Grade 2 is a safe idea. I do know that the future active use of my 52-Set will be indoors, at ambient room temperatures, for probably no more than a half hour or so, a couple of times a week, and the transmit time when the dynamotors would be active would be less than half that time.

Anybodys thoughts would be appreciated.


David