Have a goodman central air unit, non heat pump. keeps smoking transformers, on the inside unit, replaced fan capacitor and transformer as the old transformer was smoked as well. But to no avail the new transformer buzzed and smoked and acctually flamed.

Looking at the wall thermostat, you will see the fan switch that has two settings: fan auto, fan on.
You will need to place the fan switch in the fan on position for testing purposes.
This will make the indoor fan run continuosly, and never cycle off.
In the fan auto position, the fan will turn off when the thermostat temperature setting has been satisfied.
Remove the air handler access panel.
Is the air handler fan operating?
If the fan isn't working see if you can listen closely if it is humming, or can touch the motor to see if it is hot.
If it is humming and has a bad capacitor, you can tell this without having an electrical tester by spinning the fan wheel by hand.
Be very careful... making sure your hand won't get cut by the fan wheel spinning when it starts up.
If the fan spins and picks up full speed, replace the defective fan capacitor.
It is the shiny silver metallic cylindrical object with electrical wires attached to it.
Make sure you write down where those wires attach and turn the power off before removal as they carry 240 volts to the fan motor.
If you find that the fan wheel doesn't turn freely when you try to spin it by hand, the bearings have seized and you will need to find another fan motor of the same size, shaft length , speed , and horsepower to replace the defective motor.
Keep in mind that a humming sound in the air handler COULD be from the transformer instead of the fan motor.
The transformer is a black cube shaped device with electrical wires attached to it.
If the 24 volt transformer goes bad, your thermostat will not function and nothing will come on.

The fan motor is bad and needs replaced. Depending on how mechanically inclined you are, you can replace it yourself fairly easy, the hardest part being the fan blade without a hub puller. Just take your old one in with you to a local A/C supply store. The compressor is more than likely kicked off on thermal protection because of the fan motor, happens every time. After the compressor cools back down, the overload kicks back in and the compressor will start. I would also replace the capacitor while I was there, just for preventive maintience because they go out all the time, plus they are cheap. Just make sure you have the full 220v to the unit before diagnosing the problem, and make sure it is completely off when working on it, capacitors hold a charge, just in case you didn't know already. As for the Goodman problem, people never give the full story behind these units. For one, it may say Goodman on the cover, but the motor and compressor are made by the same companies other brands use, just look at the compressor brand, probably a Copeland or a Bristol used in various brands. Two, the reason that there are more negative things said about these units are simple, more units sold, more people have them, there will obviously be more to talk about. Kind of like more money, more problems. Nothing is built like it was 15 to 20 years ago. Goodman keeps their price low by not advertising for the most part. And then you have units like Lennox that are supposed to be good, cost more to buy, and absolutely too expensive when repairing and finding parts. Just so you don't think I'm a Goodman rep or anything, I prefer American Standard equipment over anything else Ha! This is of course all from a service aspect from dealing with this everyday, but still just an opinion. I hope I have helped you and get you to cooler days, and sorry about going on and on, just thought you might like a view from someone on the inside! Have a good one and good luck!

Easy: Turn the "fan" switch to on at the thermostat and see if the blower starts. If no start, check breaker at breaker box. Check service disconnect at or near the air handler. With the breaker and/or service disconnect OFF check the 3 or 5 amp fuse inside the top cover in the air handler.
Not so easy: (You must know what you are doing for this part or let an HVAC Tech do it for you) Open thermostat and firmly jump the Y and R terminals to see if you get the compressor to start for no more than 30 seconds. (don't do it more than once.) Jump the G and R terminals to see if you get the blower to start. If so, u have a bad thermostat. If not, check the transformer inside the same cover in air handler for proper voltage. (24V. Make sure you also get 220 on the opposite side of the transformer)
If the blower comes on, but the heat pump doesnt start, open the side cover of the heat pump, with the thermostat on cool, and the temp. setting as low as possible for at least 10 minutes see if the contactor is pulled in. If so, check the capacitor and see if it's blown out. Be super careful these systems operate with 220v and the amperes are enough to kill you if you make a simple mistake.

Several types out there. 99% of them use the same basic wiring.
Red is power from transformer to t'stat. Sometime there is a wire for common from transformer to t'stat too, but not always.
While is for heat. Green is for fan. Yellow is for cooling.
These 4 to 5 wires go on the terminals that are maked with letters: C=common, RH/RC is for power, W=heat, Y=cooling, G=fan.

In most cases, 2 wires from the indoor unit will go to the outdoor unit to power it for cooling. Usually connected to the yellow wired, Y terminal and common or grounded to the unit if the transformer is done in the same fashion.

If you have a heat pump, totally different animal and different wiring too.

Hope this helps you. Good Luck.

low voltage transformer could be your problem . if you have a multimeter you can check voltage from transformer should be 24v ac. a 3amp fuse is usually blown and will cause this

Look at the contactor on the condensing unit, remove the low voltage wires to the contactor and turn on the system. If the low voltage fuse doesn't blow, replace the contactor.

you say it keeps blowing the transformer? you mean circuit breaker? if it is the circuit breaker, have the wiring checked for a short, if no short do a ohm test on the compressor. it may have shorted out internaly.

YOUR the first person that has gave enough information to help in a WHILE THANK YOU SO MUCH!!

Start all over from first
I'm betting that you need a fuse in both sides of the transformer until you find the real reason they burn up.

A solenoid valve that sticks can cause the transformer to blow but so can a lot of other things, namely anything in the control circuit that uses the 24V power. A relay or contactor that doesn't pull in or a defective defrost control, a shorted wire from the thermostat.

I'm wondering if you have what we call a package heat pump meaning the both the indoor blower and out door compressor & fan are in the same section out side? OR is your a split system with an indoor section and an outdoor section?

I'm betting on the split section. In some miss-matched systems (like a Lennox indoor and a GMC out door for example) Some of the origonal Lennox heat pumps had an out door and an indoor transformer. If these trans formers were not "phased" together it could cause a problem like your having. Now you just have it in the heatign mode if I read between the lines correctly. So it makes snece that it's something with the heat. The out door unit can opperate withits own 24v but if you have back up heat inside (gas or electric Im thinking you have electric) the indoor section will come on atfter a few more degrees of heat loss (2-4'F). This is where the transformer inside will buck the one outside and somethjing has to give. The weakest point.

From what ive been told by some of the old hands I've been around if the high volt side burns out look for a low volt problem if the low volt burns out look for a line volt problem.

If this has 2 transformers like I suspect try the fuse on both sides but remember the one is hot and will remain hot all time on 220V or 1 leg of it or it might remind you. To phase these transfoprmers I believe you swtich the main lines L1 & L2 at either of the transformers. Now 1 more thing the indoor section may be using ground on the low volt side as a path for 1 side of the transformer. I believe you will ahve to do same for the other transformer too.

Hope this helps Id really like to know what you find and do.
Please ask more and you give such detail I can follow you with little trouble. Please rate me as high as you can and good luck.

the blower fan comes on,sounds like you have a dead short,check wire connections on transformer,check for burned contactor

You may be putting the incorrect transformer in. Try to get a OEM from your local HVAC dealer. Which capacitor are you referring to?