I'm making this question here because I'm a little bit confused with what I've been seeing from some old and new 1/2 hp motors.
I've bought a 1/2 hp induction motor (4-pole, single phase, capacitor start and no run capacitor) and both its standstill and pull up torque seem quite tame. Having a ~ 2 inch diameter pulley on its axis, I can easily stop it whenever I want with one hand. I'm sure that up to 3 times that torque could still be held with one hand only.
This matched well with what I saw in two bench drills, both of which also use 1/2 hp, 4-pole induction motors, the only difference being they use both a start and a run capacitor. In both cases I could stop them by holding the chuck with a single hand, and even in the highest reduction (with reasonable effort but still), which was about 1:3.5 in both cases.
I always thought that to be kinda weak but ok.
Then, last week I saw a 60 year old drill with another motor that should theoretically be similar (1/2 hp, 4-pole). But it was a 3-phase motor, which, as long as I'm concerned, should have a lower standstill torque than a single-phase motor with start capacitor, given their torque vs slip curves.
But I had no luck holding it. Even using adherent gloves and using both hands I couldn't stop it from starting in any way and I couldn't stop it while running either.
It was also in the max torque (~ 1:3.5) relation, so maybe I could stop it in a 1:1 relation, but didn't feel like it. While others could be even stopped with one hand, this one didn't even seem to slow down while using two hands.
Is there something I'm not considering here? Once all of them have the same power rating, nominal speed and reduction, I'd expect them to be at least similar in torque, but the older one seems to be just so much stronger (and the motor itself is also much bigger and heavier).