Which is more energy efficient, solenoid or BLDC motor in static weight hold?

Question

Electronics

We lift the same weight and hold it with a solenoid and a motor (motor with a gearbox).
We apply the most optimal algorithms with current reduction and so on.
Who will get hotter as a result?

The main condition is that when the power is turned off, the load drops.

Answer 1

Depends on how the suspension is set up. If the weight is placed in a magnetic field and it hangs in this field, then, as a first approximation, the motor and solenoid will eat the same (you need to create such an induction that it compensates for gravity).
The motor will win a little due to friction in the suspension units.
For clarification, of course, you need to count.
If the weight is a ferromagnetic armature that is pulled to a magnet and the field lines are closed through it, then it's another matter - due to hysteresis, you can greatly win in the current. As an experiment, pull the entrance door, there is about 100-150 kg to take off, and this lock can work from half a day from a 7Ah 12V UPS battery

Answer 2

Magnet, worm gear or motors with a brake are even more efficient

Answer 3

if you are talking about the automatic lowering of the moderator rods into the reactor in the event of a power failure, then the magnet :)
depends on what you need in the final design...

Answer 4

It will be effective to use an equalizing weight and a gearbox. In this case, you can keep the low power of the motor.

Answer 5

For this issue, a stepper motor is quite suitable, which is released when de-energized. At the same time, as has already been said here, it makes sense as a counterweight, so that the reverse motion does not allow the load to fall. In addition, steppers do not need gearboxes. The weight force to hold is selected by the appropriate type of stepper. And yes, it also heats up, but this is natural and normal for it, the temperature can be corrected by the ratio of voltage to current.

Answer 6

From a practical point of view, the question makes no sense.
If in theory to compare a "spherical" bldc and a "spherical" solenoid, then it is necessary to provide other equal conditions, which is difficult to do. In any case, we need to determine what exactly we are equalizing for comparison.
In practice, it all depends on the design. The solenoid can have an extremely small current due to a very large inductance. A BLDC with that many turns would be unacceptably slow. On the other hand, a worm geared BLDC can be de-energized altogether.
In industry (for example, in CNC machines), a friction brake driven by a solenoid is often used.