My current and "loosely held" theory is that the "hour of trial" in Rev. 3:10 is the same as the "great tribulation" of Rev. 2:22.  We are "kept from" this trial.  I used to think our experience would be a rapture, but now I don't know what it will be ... just "kept from."  The "hour of trial" may be the 40-day period from the eclipse to May 18th.  This will be the "get off the fence" or "choose ye this day whom ye shall serve" time for the folks who claim to be Christians but are the "adulterers and adulteresses" of James 4:4 who are friends with the world.

So in short: 

1. On April 8th, 8 days from now, "kept from the hour of trial" begins for those who have kept Jesus' command to persevere (Rev. 3:10).
2. The "hour of trial" is the third "great tribulation" (Rev. 2:22) and separates true believers from the world, beginning on April 8th.
3. The "hour"/"great trib" ENDS 40 days later, on May 18th, per the pattern of Jonah 3:4.
4. Then we who are alive and remain are "caught up" as 1 Thess. 4:17 is fulfilled on May 19th.
5. Also, since May 19th is Shavuot, we can expect the "dry bones" resurrection of Ezekiel 37:10-12 AND the confirmation of the covenant of Ezek. 34:27, 37:26 and Daniel 9:27.  This begins Daniel'7 70th week.
   

We'll know if I'm right in about seven weeks.

For the sake of clarity, the first "great tribulation" was the destruction of Jerusalem in 70 AD.  This is the one prophesied in Matthew 24:21.  As we see, this great tribulation was shortened so that "flesh would be saved ...for the elect's sake."

The second "great tribulation" is the one referred to in Rev. 7:14 and is most probably the global, two thousand year long "church age."  The context makes this fairly clear, though opinions still differ.  Rev. 7:9 sounds like a description of all saved people, and it maps clearly to 2 Esdras 2:42.

The third "great tribulation" is for members of the church in Thyatira (and by extension, any with those characteristics) who "commit sexual immorality and eat things sacrificed to idols" or "commit adultery with [modern day Jezebel] and refuse to repent."  This appears to be hard-hearted carnal Christians. 

Best,

Steve