I have a construction company and have several machines like mixing plant, tripper trucks, soil diggers etc. Most of the equipments lost their smoothness because the paint got peeled off. I don’t want to spend much on renovation of my machineries. Is there any possible way to get them back in good appearance?

Why don’t you search on Google to find a suitable products? I bumped into an interesting site a few days back that might help you, I think the site is Touch up Sprays (http://www.industrialtouchup.com/).
You may try.

Get a couple of high school kids, couple cans of acrylic enamel (industrial not automotive) and some brushes.
Pressure wash the stuff and have the kids paint for minimum wage.
Pit trucks don't need to look perfect at under 20' viewing distance