Nottingham spacedeck motor - driving me crazy

As you may know, that motor is never "off". The push you give to the platter seems to engage some sort of clutch to then drive the platter properly. My guess is that there is some critical loss of torque for some reason, such that the motor cannot get going up to mechanical advantage needed for 33 rpm, but it is probably barely OK to get going using the 45 rpm part of the pulley. To test that, you might try starting it at 45 and then flick the drive belt down to the 33 pulley, see if it can then stabilize at that speed.

Thanks, Rob. You are most likely correct. Fletcher's idea of how to use the motor was closely allied to that of Lloyd Walker, except Lloyd uses a much heavier platter than did any of Tom's designs (well, never saw an AnnaLog or a Dias in the flesh). I never experienced this particular issue with my Hyperspace. Occasionally I noted that the motor had crept too close to the platter, but it still worked fine to bring it up to speed. So, why does this Spacedeck work fine at 45 rpm but not at 33 rpm? I would think that belt slippage would be a factor at either speed.