Thanks for your response. The silver motor is by “Nidec”, sub-titled LEROY-SOMER (L-S is part of the NIDEC group, apparently).
Yes, further research reveals that the motors I have installed on PERIGEE/SM#396 are identified as model number MBT86M. (The MBT denotes permanent magnets, the “86” is the diameter of the motor casing in mm, the “M” is the length of the motor casing, either S|M|L.)
SPECS of the motor as shipped -> Type: MBT82M | 24V/27A/450W | 3100rpm (I noted this difference in revs as well, as this would seem to make it out of sync with the other motor, = more blipping the toggle switches). On the 82 as received, there are no ports enabling direct access to the brushes, for servicing.
Another difference is the ‘Service Code”; the ‘as installed’ unit, model 86, the service code is S2 10mn; the one supplied (mode 82), the service code is S2 5mn; I haven’t yet cracked the code on what the difference means, excepting the obvious regarding lack of service ports.
It appears that I should have the MBT86M, not the 82M. I think that perhaps the thinner 82-model is intended for an A54 (and maybe even a later model SM than #396).
When I get a response from Maud, then I’ll post an update. But in the interim, if anyone else can chime in, please do.