Gautham Achar, you need the Marklin #7226 smoke unit if you want more smoke as listed in the catalog. This is same as Seuthe No.10 I believe & that uses 10-16 Volts. This can be used on digital locos & puts out heaps of smoke. The Seuthe No.11 used on 16-22v systems. I am sure the other members will gladly give you the technical details as regards what power it draws ETC.I have Fitted a relay to my Big Boy & that enables me to use two smoke units at once via direct track power. For this I use the Seuthe No.11. Looks great but messy. Tracks get contaminated as well as you have an oily loco.
Try looking at this link: http://www.seuthe-dampf.de/start.htm & go to technical section. The Seuthe No.10 has a red bottom & the Seuthe No.11 a green bottom as far as I am aware of. Personally I like the smoke to burn longer & less intensely & hence most of my outputs on my Loksound/lokpilot decoders have their power greatly reduced for this purpose. It will be interesting to hear the opinions of others & we may all learn something new.

I haven´t tested smoke generators on my 37993, but I do have 2*7226 on my 37990. It works great and I think it should be the same on 37993. I have 37991 also, but the smoke generator contacts are connected directly to the tracks! Stupid!