Installation manual

In order to comply with standards for conducted and

radiated emission noise, the 3-Phase rectifier in your

PowerSpout may include a noise filtering module for

conducted emissions. This EMC filter in only included if your

turbine was ordered for a grid-connect application.

Rectifiers get hot due to losses and lower voltage systems

have greater losses. In a 12 V system you lose

approximately 10% of the energy you generate in the

rectifier, whereas this figure is only 3% for a 48 V system.

5.2. Unloaded rpm and Open Circuit Voltage (Voc) revisited (see also 3.5)

In a hydro turbine that is unloaded (the output wires are left unconnected), the rotor reaches

almost the same velocity as the water jet. The resultant rpm can be easily calculated for

your site data by the advanced calculation tool. The voltage of any PMA when unloaded is

proportional its rpm. This "open circuit voltage" or Voc can be high enough to cause

damage or danger.

In theory (if we ignore friction) the voltage output of a PLT or TRG turbine can increase up to

4 times for two reasons:

 The rpm theoretically increases to almost 2 x normal speed

 The Voc for an Smart Drive PMA is almost 2 x MPPV even at constant rpm

In practice due to friction the relationship between Voc and MPPV (maximum power point

voltage) is roughly as follows:

 PLT and TRG turbines Vo is approximately 3 x MPPV

 LH turbines Voc is approximately 2 x MPPV

5.3. PowerSpout standard voltage options

5.3.1. PowerSpout PLT and TRG turbines

PLT and TRG turbines are identified by voltage to suit the site and system design e.g.

connected directly to battery banks, connected to battery-based MPPT controllers or to grid-

connect inverters. The turbine abbreviation (PLT, TRG) is followed by a number that

indicates the approximate "maximum power point" voltage or MPPV, which is also the

operating cable voltage. This will be close to the voltage the turbine produces when the

speed is optimised for maximum power depending on how accurate the design data

(estimated head, etc) proves to be in reality. For example:

 PowerSpout PLT 28 has an MPPV of 28 V (connects directly to 24-volt battery bank with

PWM diversion controller). 28 V is the "bulk charging" voltage for a 24-volt battery.

 PowerSpout PLT 200 has an MPPV of 200 V (connect to grid via grid-tied inverter)

5.3.2. PowerSpout LH turbines

For PowerSpout LH turbines, for example the LH200, the 200 is not the MPPV but the

maximum Voc at turbine runaway. This is because there are no LH turbines that connect

directly to batteries. All LH turbines require MPPT regulation for battery charging or the use

of a grid connect inverter.