CREATE TABLE table_27126 ("Wind farm" TEXT, "Installed capacity  ( MW ) " TEXT, "Turbine Manufacturer" TEXT, "County" TEXT, "Date in Service" TEXT)

How many turbine manufacturers installed a capacity of 189 MW?
SELECT COUNT("Turbine Manufacturer") FROM table_27126 WHERE "Installed capacity (MW)" = '189'
SELECT COUNT("Turbine Manufacturer") FROM "table_27126" WHERE "Installed capacity (MW)" = '189'