I had a stackable Kenmore washer/dryer. It was equpied with the 3 prong electrical cord. I was able to wire it to a double 30a circuit that was in my home that only had a white and a black wire and it worked for years. I recently bought a new dryer but it will not work when I wire it the same way. It will start for a minute then shut off. I wired it to another circuit that my stove was on and it works now but i need to wire it to a differnet circuit so they are seperate.
To play it safe its best for you to get a certified electrician and have it done according to code, because from what you describe you are missing a safety ground and splicing wires that should not be spliced (dedicated circuit for your stove and one for your washer laundry system), this can lead to a fire and/or shock hazard.