The medium pressure (MP) section of the
station was completed in two phases - 1929 and 1931 - and ultimately comprised four boilers and two
turbo alternators together with an 11,000 volt metal clad switch room
constructed during the second phase.
The boilers were nos. 9,10,11 and 12 and the turbines nos. 5 and 6. Note
at the time of construction this section was referred to as the High
Pressure Section.
The Boiler operating pressure was 265 psi
at 650 deg F (343 deg C) with the turbine inlet at 250 psi. The
alternator outputs were 7,500 kw Maximum Continuous Rating (MCR) with an Economic Continuous Rating (ECR) of
6,000 kw and switched at 11,000 volts. The
alternators ran at 3000 rpm. Boilers 9 and 10 had an evaporation rate
greater than 40,000 lbs/hr whilst boilers 11 and 12 had an evaporation
rate of 50,000 lbs per hour. The coal bunkering system was designed to
receive two fuel types - coal and coke. The original coal supplies were
from the Forest of Deane and coke was a by-product of local coal gas
production. The boiler fire comprised a sandwich of the two fuels
with coke as the lower.
Below is a copy of the programme that
brings No 6 Machine into commission on the 19th November 1931. (Number 5
machine was fully commissioned on 1st May 1929). At this
time the station was still operating as an 'islanded' source of
electricity providing supplies to both Newton Abbot and Torquay as well as
the China Clay pit areas of the Teign Valley. An interesting fact of the
time is that the average annual consumption of electricity per person was
little more than twenty units per year. Of course electricity at that time
went to the very few but it is an interesting reflection of how things
have changed.
Following the commissioning of the
second Medium Pressure machine - No 6 - in 1931 a 132,000
volt connection from Exeter and onwards to Plymouth and Hayle was
established and the first stage of what we now know as National Grid
created in 1934. This single connection meant the station was still at risk of
being islanded and was on numerous occasions but started the period of
shared spare generating capacity and economic 'merit order' operation.
Turbo Alternator Number 6 - Fixed
blades and steam rotor
Turbo Alternator Number 6 - Stator
and Rotor
Cooling water to supply the MP Turbine
condensers was drawn from the Number 2 pump house located on the banks of the
River Teign. This pump house also provided top up water for the cooling
tower yet to be built and cooling water returned to the River Lemon a
confluent of the River Teign.
