Whipping wonders gives a penalty yes.
1 population lost to the whip no longer gives 30
when whipping a wonder. (Normal Speed)
The penalty depends on the Wonder's hurry cost modifier.
Here are the iHurryCostModifier from the BTS XML folder in case anyone wants the full list of 48 Wonders.
iHurryCostModifier = 50
Palace
Forbidden Palace
Globe Theatre
Hermitage
Heroic Epic
National Epic
National Park
Oxford University
iHurryCostModifier = 100
Angkor Wat
Chichen Itza
Colossus
Cristo Redentor
Great Library
Great Lighthouse
Great Wall
Hagia Sophia
Hanging Gardens
Mausoleum of Maussollos
Notre Dame
Oracle
Parthenon
Pyramids
Shwedagon Paya
Sistine Chapel
Spiral Minaret
Statue of Zeus
Stonehenge
Taj Mahal
Temple of Artemis
University of Sankore
Versailles
Ironworks
Moai Statues
Mt. Rushmore
Red Cross
Wall Street
West Point
iHurryCostModifier = 200
Kremlin
Eiffel Tower
Statue of Liberty
Broadway
Rock 'n' Roll
Hollywood
Three Gorges Dam
Pentagon
iHurryCostModifier = 300
Apostolic Palace
United Nations
Space Elevator
All that means is that
after putting 1 or more into a build, whipping a iHurryCostModifier=50 wonder will produce 20
per population whipped.
Whipping a iHurryCostModifier=100 wonder will produce 15
per population whipped.
Whipping a iHurryCostModifier=200 wonder will produce 10
per population whipped.
Whipping a IHurryCostModifier=300 wonder will produce 7.5
per population whipped.
Whipping at 0
in a build is penalized and you generally only get 66% or 2/3rds of the hammers you would normally expect.
Production Modifiers like Forge + Factory + Coal plant only apply
after the penalty from whipping at 0
and/or whipping a wonder is applied.
A city with +100% production bonus whipping a United Nations complete with 0
in the build can expect (7.5*2/3*2) = 10
per population whipped.
The Kremlin wonder has a huge effect on whipping, but it is too complicated to explain exactly how it works.
Just treat your 1pop whips like 44
(instead of 30) and your 2pop whips like 89
(instead of 60). This is for whips with more than 0
already invested.
Kremlin whipping with 0
invested is penalized to 2/3rds, and 1pop whip is 30
and 2pop whip is 60
Projects like Internet and Apollo can't be whipped.
The kind-hearted wiki you linked made an error about whipping Globe Theatre.
It will produce 20
per population when whipping, not 22.5.