That appears to be an Allen-Bradley built motor drive with a bypass contactor enclosure on the bottom. It's an open loop vector drive, or flux vector. Not as popular as inverter drives, and it costs more than a typical inverter drive. It's used when motor speed control is very important(.1%). This drive can deliver full rated torque at zero speed, with full torque control.
It's used for a pretty specific application.
I'm guessing the lower cabinet holds the electro-mechanical contactors. This is typical where reliability is very important. Examples: Municiple water pumps, cooling towers/fans, high production manufacturing or food processing. In the event of a drive failure, you can switch it to bypass and run the load at full rpm without the drive working. This would also be done during maintenance of the drive.
If the drive works, which would be very easy to test, it's worth something. I installed a new 20 horse yesterday at $6400. The problem is, drive packages are designed specific for your needs. It's often engineered by a mechanical engineer specific to the load and atmosphere. They can be designed with an emphasis on constant torque, variable torque, constant speed(rpm/gpm), or constant horsepower. So this drive may not work right for your prospective purchaser.
The operators on the lower cabinet are about $50 each new. The lockable disconnect is $100 new. You may be able to sell this for parts. I've replaced several of these at mills, cement batch plants, rock crushers, etc. They break them all the time.
