Hammond Power Solutions INDUSTRIAL CONTROL TRANSFORMERS General Product Line Information
SECTION 1
CONTROL TRANSFORMER SELECTION
INDUSTRIAL CONTROL
TRANSFORMERS
Selecting a Control Transformer
requires that you have first hand
knowledge of the application for the
transformer and that you understand
some basic terms related to the
selection process. By using the following information, you will be sure to
select the HPS Control Transformer
which best meets your application.
Th e H P S I m per a tor Se r ies
machine tool control transformers
SECTION 1
are specifically designed for high
inrush applications requiring reliable
output voltage stability. Designed to
meet industrial applications where
electromagnetic devices such as
relays, solenoids, etc. are used, the
HPS Imperator series transformers
ma ximi ze inrush capa bility and
ou tput volt age regulatio n when
electromagnetic devices are initially
energized.
To select the proper transformer,
three characteristics of the load
circuit must first be determined.
They are total steady-state (sealed)
VA, total inrush VA, and inrush load
power factor.
1 (A). The total steady state
“sealed” VA is the amount of VA
that the transformer must supply
to the load circuit for an extended
length of time. Simply add the total
steady-state VA of all devices in your
control circuit. The operating VA data
of these components is available
from the manufacturers.
1 (B). The total inrush VA
is th e amoun t of VA that the
transformer must supply for all
components in the control circuit
which are energized together.
Some consideration to the start-up
sequence may be required. Inrush VA
should be obtained from the device
manufacturer.
1 (C). The inrush load power
factor is difcult to determine without
detailed vector analysis of all the
control circuit components. Such
information is not generally available.
Therefore, HPS is recommending
that a value of 40% power factor
be utilized. Although some other
control transformer manufacturers
still recommend a power factor of
only 20%, HPS, through recent tests
conducted on many popular brands
of control devices has determined
that the 40% power factor value is
more accurate.
Once the above circuit variables
have been determined, transformer
selection is a six (6) step process.
SIX EASY STEPS
1. Determine what your Primary
(supply) and Secondary (output)
voltage requirements are, as well
as your required frequency (i.e. 60
Hz)
2. Calculate the Total Sealed VA
of your circuit. (See Step A)
3. Now ca lculate the Inrush
VA by add ing the inru sh VA of
all components being energized
together. Remember to add the
sealed VA of all components that do
not have inrush VA, (lamps, timers
etc.) as they do however present
a load to the transformer during
maximum inrush. If the inrush for
the components in your circuit are
not known, assume a 40% Inrush
Power Factor.
4. Calculate the Total Inrush VA
using one of the two methods:
A. Total Inrush VA =
(VA sealed)2 + (VA inrush)
OR
B. Total Inrush VA =
VA Sealed + VA Inrush
Note: method B will result in a slightly
larger transformer being selected.
For VA sealed denition please refer to 1 (A).
For VA inrush denition please refer to 1 (B).
2
5. If the nominal supply voltage
does not uctuate more than 5%,
then reference the 90% secondary
voltage column in the Regulation
Data Table for the correct VA
rating.
If th e supp l y voltage varies
upwards of 10%, the 95% secondary
voltage column should be used to
size the transformer.
C u r re n t s ta n d ar d s r eq u i re
electromagnetic devices to operate
rel i ably at a minimum of 85%
of their rated voltage. However,
contact life may be affected with
continuous start-ups at that voltage
level. Therefore, the minimum 85%
secondary voltage column should
only be used as a reference.
6. Using the regulation data tables
below, select the appropriate VA
rated transformer:
A) With a continuous VA rating that
is equal to or greater than the value
in Step 2.
B) With a maximum inrush VA
equal to or greater than the value
obtained in Step 4.
To determine the correct HPS
Transformer and its Catalog Number,
just refer to the tables in this catalog
for the voltage ratings, frequency
and corresponding VA required.
“HPS IMPERATOR” TRANSFORMERS
REGULATION DATA TABLE
Continuous VA Inrush VA @ 40% Power Factor
Transformer 85% 90% 95%
Nameplate Secondary Secondary Secondary
Rating Voltage Voltage Voltage
50
75
100
150
250
350
500
750
1000
1500
2000
3000
5000
It is recommended that a Control Transformer be
sized at a 40% Power Factor. Some components
in a circuit, such as electromagnetic devices,
typically operate at that level due to their
inherently lower power factor. Selecting a
transformer at 40% Power Factor will more than
adequately size the unit for all the various loads
in the circuit.
330
350
620
895
1596
2464
3939
6422
9842
12797
17833
37406
55629
259
258
467
699
1229
1889
2854
4778
7102
9018
12656
26217
38788
192
170
321
512
880
1345
1819
3228
4530
5489
7865
15940
23601
© Hammond Power Solutions Inc.
32
Data subject to change without notice.
SECTION 1
HPS IMPERATOR
SECTION 9
HPS ImperatorTM Series Control Transformer - Applications
TM
The Perfect Solution
The HPS Imperator series of machine tool industrial
control transformers are specically designed to meet the
high inrush industrial applications where electromagnetic
components such as relays, solenoids etc. are used.
With 11 standard voltage groups, a VA range from 50VA to
5000VA and available with standard secondary and optional
primary fuse kits, the HPS Imperator series from HPS
provides the perfect solution for any applications.
Superior Quality and Value
The HPS Imperator series design, utilizing superior
insulation systems and being constructed with high quality
silicon steel laminations for optimum performance, will meet
or exceed cUL and CE standards.
Backed by an industry leading LIFETIME warranty, the HPS
Imperator industrial control transformer line offers superior
performance, quality and value.
Innovative Design
The HPS Imperator series is a unique, fresh and
innovative compact design that provides the ideal
solution for any industrial control application and will
change the way the industrial machine tool industry looks
at the control transformer.
The HPS Imperator’s unique terminal block design
(patent pending) allows for the quick and easy
installation of standard secondary or optional primary
13/32” x 1 1/2” midget/type CC fuse clips on every unit.
This is the simplest and most inexpensive fusing
installation provided on any industrial control transformer
in the market today.
The windings and internal terminations of the HPS Imperator are encapsulated, which protects them from moisture, dirt and other airborne contaminants. The custom
molded coil covers with their unique ‘n shaped’ design
combine superior transformer cooling properties with a
clean bold look.
The HPS Imperator utilizes custom serrated terminals, in
combination with standard SEMS washer screws making
assembly easier and quicker to install; and provides superior connection strength when connecting with bare, solid
or stranded wire. It also allows for ring or spade termination connectors.
SECTION 1
STANDARDS
HPS Industrial and Machine Tool Control and Instrument Transformers meet or
exceeds the standards established by UL, IRC, ANSI, NEMA.
Standard File # VA Size
UL (ANSI/UL 506) E50394 All PH
IEC 61558 All PH (excluding PH***AJ & PH***AR)
NEMA (ST-1) All PH
At HPS, we rate the VA capacity of our transformers at the output ..... where it counts.
Other transformer manufacturers rate their capacity on the input side of the
transformer, which can result in a 5% to 20% lower actual VA at the output.
© Hammond Power Solutions Inc.
33
Data subject to change without notice.
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