Overvoltage Protection Adjustment - KEPCO HSM 3.3-230 Operator's Manual

Measurement quantities are defined as follows:
V , VSET: This voltage represents 1/10 of the programmed output voltage. As an example,
O
VSET (or V
This relationship is constant, regardless of the programming range selected (see PAR.
3.4).
I , ISET: This voltage represents the percentage of available power supply current as a per-
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centage of rated current, with 10V corresponding to 100%; available current is defined
as the maximum current limit available based on the programming range (see PAR.
3.6). Unlike VSET, ISET is always based on a 0-10V scale, regardless of the range
selected. For example, ISET (or I
programmable current; for the low programming range, this corresponds to 62% of the
rated module current, but for the high programming range the number is 62% of 110%,
or 68.2% of rated module current. If the module is HSM 5-200, for example, the pro-
grammed current limit is either 124A or 136.4A, depending on the range selection.
Current setpoint monitor accuracy is ±5%.
3.8

OVERVOLTAGE PROTECTION ADJUSTMENT

HSM power supplies incorporate output overvoltage protection (OVP) circuitry which latches the
output regulator off in the event that the output voltage rises above a predetermined level.
Reset requires that the user remove source power for a minimum of 30 seconds (optional
remote reset is described in PAR. 3.12). The trip level is preset at the factory for 130% of the
nominal output voltage (see Table 1-1), however, this level can be adjusted from 100% to
140% of the nominal output (except Model HSM 48-21, which can be adjusted from 100% to
160% of the nominal output) via the OVP ADJUST control accessed through the top cover
(see Figure 2-1). To set the trip level to a new value, perform the following steps:
NOTE: For 48V Models only, do not set OVP trip level above 63V.
1. Disconnect any external load circuitry which may be damaged by excessive voltage; a mini-
mum load of 5W is recommended (see PAR. 2.5, step 3).
2. With source power removed, connect load as shown in Figure 2-4 for local sensing, except
remove connection between I/O connector pin 37 (+S) and the output bus bar and substitute
a 20K ohm potentiometer between pin 37 and the output bus bar; adjust the pot for minimum
resistance.
3. Rotate OVP ADJUST control on HSM fully clockwise.
4. Apply source power; while monitoring voltage at output terminals (bus bars), increase exter-
nal pot resistance until the output voltage is set for the desired overvoltage protection value.
5. Slowly rotate the OVP ADJUST pot counterclockwise until the output is latched off (voltage
drops rapidly toward zero); the overvoltage trip level is now adjusted to the desired overvolt-
age protection value (step 4, above).
6. Remove source power for 30 seconds, or until the internal fan stops turning; reduce the
external pot resistance slightly, and reapply source power.
7. While monitoring the output voltage, slowly increase the pot resistance until the output shuts
down, and verify trip set point; if necessary, repeat steps 3 through 6 above.
3-4
) = 4.63V corresponds to a programmed output voltage of 46.3V ±1%.
O
) = 6.2V corresponds to 62% of the maximum
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HSMSERIES OPR 052912