Will not spin fast enough to whip cream

It will be a broken or missing pin through a gear or the planetary or something wrong with the fuse gear. It should be easy enough to find but you will need to split the gearbox cases to check.

Make sure your Beater can slip in and out of the Beater Shaft
easily. Do not force the beater onto the Shaft if the shaft is bent.
If it cannot be removed easily by hand, use a soft rubber mallet
(not a steel hammer) to slightly tap the beater so it can be moved
up and down the shaft or from side to side. Then you can easily
turn the beater left and remove it from the shaft.

From Kitchenaid Manual:
To Attach Flat Beater, Wire Whip, or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Slip beater onto beater shaft and press upward
as far as possible.
5. Turn beater to right, hooking beater over pin on shaft.
6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft

Make sure your Beater can slip in and out of the Beater Shaft

easily. Do not force the beater onto the Shaft if the shaft is bent.

If it cannot be removed easily by hand, use a soft rubber mallet

(not a steel hammer) to slightly tap the beater so it can be moved

up and down the shaft or from side to side. Then you can easily

turn the beater left and remove it from the shaft.

From Kitchenaid Manual:

To Attach Flat Beater, Wire Whip, or Dough Hook

1. Turn speed control to OFF.

2. Unplug stand mixer or disconnect power.

3. Tilt motor head back.

4. Slip beater onto beater shaft and press upward

as far as possible.

5. Turn beater to right, hooking beater over pin on shaft.

6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook

1. Turn speed control to OFF.

2. Unplug stand mixer or disconnect power.

3. Tilt motor head back.

4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft.

Make sure your Beater can slip in and out of the Beater Shaft
easily. Do not force the beater onto the Shaft if the shaft is bent.
If it cannot be removed easily by hand, use a soft rubber mallet
(not a steel hammer) to slightly tap the beater so it can be moved
up and down the shaft or from side to side. Then you can easily
turn the beater left and remove it from the shaft.

From Kitchenaid Manual:
To Attach Flat Beater, Wire Whip, or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Slip beater onto beater shaft and press upward
as far as possible.
5. Turn beater to right, hooking beater over pin on shaft.
6. Plug into a grounded 3 prong outlet.

To Remove Flat Beater, Wire Whip or Dough Hook
1. Turn speed control to OFF.
2. Unplug stand mixer or disconnect power.
3. Tilt motor head back.
4. Press beater upward as far as possible and turn left.
5. Pull beater from beater shaft

Get a copy of the Repair Part List for your model at Kitchenaid.com
Download the following Kitchenaid Service Manual:
http://www.kitchenaidparts.be/centers/servicemanual/mixer.pdf

It covers several models including yours.
1. Check/Adjust the Flat Beater to Bowl Clearance:

Turn screw (A) SLIGHTLY counter clockwise (left) to raise the flat

beater or clockwise (right) to lower the flat beater
2. Check the Beater Shaft (Agitator Shaft) making sure the Retaining ring
is flushed with the surface of the Planetary Assembly
Constant Pulling and Removal of the beaters can cause the Agitator shaft to move
3. If the above two still don't solve your problem, follow the service manual
directions to disassemble the Planetary Assembly and check for loose screws

The Hobart H600 is a 2 horse power, 60 quart mixer, it can be used for many things in the kitchen. It can be used to make about any kind of food that needs mixed, wiped or kneaded. It works well in a pizzeria for all facets of making pizza from the dough, to shredding the cheese with an attachment, to a restaurant that makes mashed potatoes and fresh bread, to a full service bakery.
However, the biggest thing that you need to know is the capacity of the machine. As overloading the machine can cause damage that may be costly and take a technician to fix. I do not know what attachments you currently have so I will go over a few of them.

The main attachments are a Wire whip, Flat beater, and Dough hook. There are three different types a "D" wire whip (has many wires and is evenly spaced) this is used to whip egg whites, whipping whip cream, etc. The "C Wing" (has six tines in it) is used for items that are heavy for the D wire whip, like whipping potatoes or icing. The last is the "I" whip is similar to the D wire whip just with less tines. The flat beater is used to mashing or mixing examples are mashed potatoes before they are whipped, cake mixes that do not require whipping, batters and icing. The Dough hook is used for kneading dough examples are pizza dough, bread dough, etc.

The biggest thing when using your mixer is to know its capacity for the material that you are mixing. All though this is one of the bigger machines it still has limits. You should refer to this the following link for the capacity of your machine: https://my.hobartcorp.com/resourcecenter/ProductDocumentation/F-7701.pdf

There are also a few attachments that can be put on to the No. 12 attachment hub. A few of these are a vegetable slicer-grater and meat grinder.

I don't beloeve mine will turn fast enough to do whipped cream quickly.

make sure you are using the right attachment. usually for batters you want to use the flat beater. not the dough hook. the flat beater looks like a triangle with lines through the center. and make sure you are using the correct speed on the mixer. start out at stir and then go up to no more than half speed. these mixers take a little longer to incorperate batters but they do a very good job at it. if the batter is thin enough you can try using the wisk as well. but only if it is a thin batter.

Mine did almost the exact same thing one day. I have the Artisian Model, It would do it on any of the lowest speeds. Dont know if this will help you or not but I just ran mine the next day on all the way high with the spash guard on for making whipped cream for about 6 minutes full throttle and for some reason it hasnt went slow and shut itself off since then. Mine is about 7 months old. I called Kitchen Aid but their customer service all of a sudden seems to not know english worth a poo...

Try running yours on full blast for 5 minutes with something simple in the bowl. If its a 250 watt or higher make whipped water out of 2 cups of water and a tablespoon of cornstarch. Run it till you get what looks like whipped cream. Oh yea. Use the Balloon whip. The lubrication in the motor is supposed to last for at least 5 years but I have seen on numerous post's that if you run them on all the way for at least 5 minutes the oil will even out in the motor. Running the mixers at low speed alot will cause the oil inside not to move as freely since the motor doesnt heat up the oil in the gears.

Good luck.