Basler Electric BE1-60 - Manual (Page 11)

9170700990 Rev D BE1-60 General Information 1-3
Since Circuit 1 is nominally rated at 120 Vac, the three-phase voltages of Circuit 2 are defined as line-to-
neutral for a type E wye input or line-to-line for a type F delta input. This apparent voltage difference is not
sufficient to produce a response if the pickup setting is G, H, J, or K since these settings represent
voltage differences of 42, 48, 54, and 60 volts respectively. Therefore, it is recommended that the lower
pickup settings be used for relays with sensing input styles E or F.
OPERATIVE EXAMPLE
The following example details the effect that the BE1-60 would have on the system shown in Figure 1-1.
Given: Potential transformer secondary voltages are 120 Vac
BE1-51/27R pickup setting is 4.5 Aac
BE1-60 pickup setting is B (10%)
Assume that a fault causes the sensing potential transformer secondary voltage to dip 9% to 109.2 Vac.
Characteristically, the BE1-51/27R will pickup and start timing when the line current reaches 4.095 Aac
(instead of 4.5 Aac) as determined below.
A 4.095 (91%) A 4.5 9%) (100% A 4.5
= = −
This will result in the BE1-51/27R producing an undesired trip. The trip is undesired because the current
pickup level has been inadvertently lowered by the voltage dip seen on the secondary winding of the
sensing transformer—even though the line voltage has not changed.
Now assume that the fault causes the sensing potential transformer secondary voltage to dip 10% to 108
Vac. This will cause the BE1-51/27R to pick up and start timing at 4.05 Aac as shown below.
A 4.05 (90%) A 4.5 10%) (100% A 4.5
= = −
However, since the voltage dip seen on the secondary winding of the sensing potential transformer meets
the 10% pickup setting of the BE1-60 and the secondary voltage of the power potential transformer has
not changed, any undesired trip signal from the BE1-51/27R will be blocked by the BE1-60 Circuit 2
output contacts.
MODEL AND STYLE NUMBER
The electrical characteristics and operational features of the BE1-60 relay are defined by the model
number and style number. The model and style numbers appear on the relay front panel, draw-out cradle,
and inside the case. The model number BE1-60 identifies the relay as a Basler Electric Class 100 Voltage
Balance Relay. The style identification chart for the BE1-60 relay is shown in Figure 1-3.
Sample Style Number
The style number identification chart of Figure 1-3 illustrates how the BE1-60 relay’s operating
characteristics are determined. For example, if the style number were D1H-A1R-C0C2F, the BE1-60 relay
would have the following features.
D---------- three-phase wye to three-phase delta sensing input
1 ---------- sensing range of 60 to 125% of nominal
H---------- two normally-closed output relays (one per monitored circuit)
A1 -------- instantaneous timing
R---------- operating power derived from 24 Vdc source
C---------- two internally operated targets (one per circuit)
0 ---------- no power supply status output
C---------- push-to-test outputs (pushbuttons)
2 ---------- normally-closed auxiliary output contacts (one per circuit)
F ---------- semi-flush case mounting