Need help controlling a 90VDC motor

Hey Guys, i hope you can help me!

My problem is as follows: I want to control a DC motor using my Arduino Mega's PWM output. I read a few things here and there and if i got it right i need an H-Bridge with MOSFETS and a H-Bridge driver IC to prevent shoot-through and a short between 2 serial mosfets in my bridge. I hope this isnt totally wrong. I'm really new to this level of electronics and i have problems adapting existing shematics to my needs, as i need to power a rather exotic motor (at least i couldn't anything similar out there). So if anyone can give me any pointers on where to start, which parts to use or maybe a completely different way of controlling it im all ears. The motors specs are:

HP 1/4 90VDC 2.0A RPM 165 Torque 70 IN. LBS. Ratio 15:1

Any ideas on providing the required 90VDC would also be great. The machine itself is powered with a standard european AC outlet providing 240VAC at 50Hz. ATM the motor is controller with a rather strange looking PCB which can drive it with 3 different speeds and hast some other adjustments. if it helps i can post a picture of that particular part. The problem with it is the inconsistency with which it drives the machine. AFAIK i can use the arduino to controll the motor via PWM/HBridge and keep it at a constant speed even if loads change. An independant speed-sensor is built into the machine so i would just have to program it so keep a certain speed. Thats my theory anyways. I hope i am not batshit crazy trying to do this. Any help would be great and sorry for the ramble!

TL;DR: need to control 90VDC motor with H-Bridge/Driver/Arduino combo. Which parts are best to use and what is the best way to get my 90VDC from mains-voltage?

It sounds like your machine already has the appropriate motor driver board installed. Get a picture of that board and post it here so aomeone can give you some advice on how to go about getting the information you need. It probably has a method of feeding it an analog signal, and may be using it already to control the 3 speeds.

Thanks for the reply! The problem with the installed controller is that it uses 3 pots for the 3 different speeds and 3 more to set accerleration, braking and load/no-load difference. It also produces the required speeds/voltages quite unpredictable. My goal was to build a motor controller that can drive the motor at any speed i set in the programming instead of 3 discreet speeds. Controlling the motor this way via PWM would be a great benefit especially because i can monitor motor speed on the go and adjust accordingly with the software. The load/no-load differentiation would also be a simple matter of programming instead of this strange circuitry. But i will post the picture of the controller here nonetheless. Maybe it makes things easier. Sorry for the bad quality, but i dont have access to the machine right now and this is just a crappy cellphone pic of a printed crappy cellphone pic -.- Next time i have access to it i will take a better picture.

http://imgur.com/KIaU4

IR2184, IR21844, IR2109, just some examples of half-bridge drivers. You need two of them, plus 4 mosfets, to drive a motor.

Beware: your motor is 1/4HP. That is not very much, but still enough to do some serious damage to things around, but also to itself. If you just 'put it on', without any control, it will very likely destroy itself in some time. Apply some kind of soft-start. Also, I advise you to monitor the motor current. This way you can determine wether the motor has to deliver torque, and if it's jamming or something (too much current).