Term
Abbreviation Explanation
Tie breaker
TB
Used to connect/disconnect the emergency busbar from the main busbar. The
EMERGENCY genset controller can control a tie breaker. (Note: The breaker
between two main busbars is called a bus tie breaker.)
Time
t
Time delay
An alarm must exceed its set point continuously for the period in its Time delay
parameter before the alarm is activated.
Transmission control
protocol/internet
protocol
TCP/IP
The Internet protocol suite. It provides end-to-end connectivity by specifying data
handling.
Trip
An emergency or fast opening of a breaker. No attempt is made to de-load the
breaker before it opens.
Voltage
V
Electrical potential difference. U is used as an abbreviation for voltage in most of
Europe, Russia and China.
Voltage and
frequency
V & Hz
For certain controller actions, both the voltage and frequency must be within the
specified range. For example, for busbar OK, or to start synchronising a genset to
the busbar.
19.2 Units
19.2.1 Units
The table below lists the units used in the documentation, as well as the US units where these are different. In the
documentation, the US units are given in brackets, for example, 80 °C (176 °F).
Table 19.1
Units used in the documentation
Unit
Name
Measures
US unit US name
Conversion
Alternative units
A
ampere
Current
bar
bar
Pressure
psi
pounds per
square inch
1 bar = 14.5 psi
1 bar = 0.980665
atmosphere (atm)
1 bar = 100,000
Pascal (Pa)
ºC
degrees Celsius
Temperature
ºF
Fahrenheit
T[ºC] = (T[ºF] - 32 º) ×
5 / 9
T[ºC] = T[Kelvin
(K)] - 273.15
dB
decibel
Noise or
interference (a
logarithmic scale)
g
gram
Weight
oz
ounce
1 g = 0.03527 oz
g
gravitational force Gravity,
g
= 9.8 m/s
2
ft/s
2
g
= 32.2 ft/s
2
h
hour
Time
Hz
hertz
Frequency (cycles
per second)
kg
kilogram
Weight
lb
pound
1 kg = 2.205 lb
PPM 300 PICUS manual 4189341080 UK
www.deif.com
Page 203 of 213
