ECV85D2 (Directly Proportional Electro-hydraulic Converter)
Product Guide
ECV85D2 (Directly Proportional Electro-hydraulic Converter)
Product Guide
T
A
ECV85D2 Operating Scheme
The ECV85D2 is a “direct command” electro-hydraulic
converter, designed for a typical power oil pressure in
the range of 0.8 to 5 bar.
Although it operates with a relatively low-pressure
range, no special settings or adjustments are
required, however it still ensures a reliable and
uninterrupted performance in a wide range of
operating conditions.
ECV85D2 is used as a current to pressure transducer
to drive hydraulic servo actuators and provides a
regulated output pressure directly proportional to the
control current.
The regulation is optimized for a wide range of flow
rates. The flow limitation is outside the converter and
is typically implemented by means of calibrated
orifices.
The flow rate is regulated by means of a “swing-disk”,
whose positioning is established, on one end, by the
solenoid’s mechanical force which is proportional to
the control current and on the other end by the
opposing force due to the pressure of the oil.
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The pressure drop across the calibrated orifice, that
depends on the oil flow discharged, establishes the
pressure under the swing disk thus regulating the
output oil pressure.
In case of zero current, the pressure drops below the
minimum of the regulating range.
From the structural point of view, ECV85D2 consists
of a manifold fitted with a solenoid, a valve seat,
connections for the pipes, as well as connections for
the control instruments.
The resulting structure is compact and easy to install,
and the need of connecting pipes is reduced to a
minimum.
ECV85D2 is normally used in a closed loop system;
the feedback signal is in this case a modulated oil
pressure, provided by a transducer, directly fitted in
the converter casing.
In this configuration, all the static errors (non-linearity,
hysteresis, and insensitivity) are cancelled without
impairing the dynamic performances.
ECV85D2 (Directly Proportional Electro-hydraulic Converter)
Product Guide
Driven with pressure feedback
FEATURE
NO
YES
Modulated oil pressure range
0.8 ÷ 5.0 bar
Current full range (*)
0 ÷ 1100 mA
Linearity range –
modulated Oil pressure
Linearity range –
current
0.8 ÷ 5.0 bar
300 ÷ 1100 mA
Maximum regulated flow rate
70 l/min
Allowable Overflow – no drive current
80 l/min (Fig. 7)
Characteristics (1 ÷ 5 bar):
Non linearity
<2%
0.1%
<3% max.
Zero
Insensitivity
<0.4%
Zero
Short term drift
<0.05%
Zero
<2%
0.1% / year
Average hysteresis
o
Long term drift (from 30 to 50 C)
Ambient operating temperature
–25 ÷ +70°C
Dimensions max. ( W x D x H)
110 x 345 x 375 mm
Oil input connection
1 ½” G
Oil discharge connection
(*)
2” G
The driving current signal must have a superimposed dither of about 10-15% @ 75 Hz.
ITEM
CODE
ECV CONVERTER, equipped with damper and magnet
ZSIE.225.652.000.00
Pressure transducer
ZSIE.534.071.000.00
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ECV85D2 (Directly Proportional Electro-hydraulic Converter)
FIGURE 1
1
Connector for solenoid power supply
2
Oil discharge
3
Modulated Oil
4
Pressure Transmitter
5
Pressure Transmitter Connectors
6
Fast lock for SMA-3 flexible pipe for inlet pressure meter
7
Mounting holes
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Product Guide
ECV85D2 (Directly Proportional Electro-hydraulic Converter)
The converter must be mounted in vertical position,
higher or lower than the servo actuator, to allow the
discharge of possible gas “pockets” through the
converter or the servo actuator.
The pipes should be installed with a minimal slope to
avoid gas “pockets” generation. The converter must
be fastened to an anchor plate by means of dedicated
screws.
Product Guide
When the difference between the servo actuator and
the converter height is greater than 0.5 m, the
hydrostatic pressure should be taken into account.
The overall dimensions and the placement of the
connections are shown in Figure 1.
Figure 2 shows the typical flow diagram of the
converter.
A
FIG. 2 – BLOCK DIAGRAM WITH SERVO ACTUATOR
IMPORTANT
«» EACH ECV85D2 CONVERTER IS FACTORY ADJUSTED AND THEN SEALED IN EACH CLOSURE POINT.
«» ANY OPERATION OF PRODUCT DISASSEMBLY AND OPENING MUST BE PERFORMED ESCLUSIVELY BY
ABB QUALIFIED PERSONEL. ANY EXCEPTION AND ALTERATION, FOR EXAMPLE IN CASO OF SEAL
BREAKAGE, WILL VOID THE PRODUCT GUARANTEE.
NOTE: The plastic caps should not be removed before the fitting of the pipes to prevent the internal accumulation of
dust or particles inside the unit.
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ECV85D2 (Directly Proportional Electro-hydraulic Converter)
The connecting
assembling.
pipes
shall
be
pickled
before
The use of flexible pipes should be avoided. If this is
not possible, their length shall be limited to a
minimum.
Product Guide
Use a mineral oil with a viscosity ranging from 1.2 to
50°E (2.8 to 380 cSt). The physical and chemical
properties of the fluid must be unimpaired and it must
be free from impurities; a degree of filtration of at least
100 microns is recommended.
The cleaning of the conduit shall be performed without
the converter that should be replaced by a by-pass
pipe, sized for the double of the typical operating flow.
The following diameters and other layout topics are
recommended:
-
MODULATED OIL (inlet A): 1 ½” G connection;
-
DISCHARGE (outlet T): 2” G connection;
-
The horizontal sections must have a slope of at
least 5% in order to prevent air pockets
generation;
-
The piping must discharge directly into the tank
or into an empty pipe to avoid the risk of possible
back pressures;
-
If the horizontal layout of the piping is more than
1.5 m or if there are more than 3 elbows, proceed
with a greater pipe diameter.
In case an orifice should be used to limit the oil flow
rate, the following diagram shows the flow rate versus
the input pressure, varying the orifice diameter
(modulated oil pressure = 3.0 bar).
The orifice diameter must be chosen to keep oil flow
rate in operation below the limit of 70 l/min.
FIG. 3 - FLOW DIAGRAM
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ECV85D2 (Directly Proportional Electro-hydraulic Converter)
The wiring of the solenoid must be carried out with
adjustable and insulated connectors (pin 1 – 2: coil
connections; pin 3 free) type DIN 43650, and cable
clamp with degree of protection IP 65.
The pressure transducer wiring must be carried out
with adjustable and insulated connectors, pin 1 (+)
and 2 (-), pin 3 free, type DIN 43650, and cable clamp
with degree of protection IP 65.
The connection cables for both coil supply and
pressure transducer must be shielded, bipolar. It is not
possible to use a single shielded multi polar cable.
The shield shall extend as close as possible to the
connectors.
Product Guide
1) Check to ensure that the calibrated orifice, if any,
matches the one designed for the particular
system;
2) Check that the input pressure, measured before
the orifice, is within the range foreseen for the
system in question (normally 7 –12 bar);
3) Check to ensure that the driver module is correctly
installed and powered;
4) Activate the hydraulic inlet supply of the converter
and check to be sure that there is no leakage;
5) Change the drive current value. Check to ensure
that for 300 and 1100 mA the pressure values are
similar to those shown in diagram A (Fig.6).
To properly drive the ECV85D2, ABB Energy
Automation has developed a special module
(UTAC01) that optimizes both static and dynamic
performances ensuring the perfect efficiency of the
system.
Neither adjustment nor periodic maintenance are
required by the converter.
It is mandatory that the electrical driver provides a
control current signal with a superimposed dither of
about 10-15% @ 75 Hz.
In the event of irregular operation, check to ensure
that:
a) The calibrated orifice is not clogged;
b) The filter on the oil inlet pipe is operating properly;
The converter is normally used with a closed loop
pressure regulation. The pressure transducer,
supplied as a separate part, has the following
characteristics:
Output signal
4–20 mA
Pressure range
0–10 bar
Over-pressure max
20 bar
Linearity better than
0.1%
Zero drift
0.01% °C
Bandpass
0–1 kHz
Outlet
Ordering code
Every 20.000 working hours, it is recommended a
complete overhaul revision for the ECV85D2.
For the converter repairing or revision, the unit shall
be replaced by a spare part and sent back to ABB.
½” gas
ZSIE534.071.000.00
File: ECV85D2 - Product Guide_9AKK101130D3266.doc
c) The characteristics of the oil are conform with
those indicated.
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ECV85D2 (Directly Proportional Electro-hydraulic Converter)
Product Guide
FIG. 4 – SCHEME FOR THE TEST RIG
NOTE
(i) the following diagrams refer to the typical operating characteristic of the converter
(ii) the tests where carried out using mineral oil with a viscosity of 30°E and a temperature of 50 °C, with an
inlet supply pressure of 6 bar
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ECV85D2 (Directly Proportional Electro-hydraulic Converter)
Product Guide
!"
FIG. 5 – TYPICAL OPEN LOOP P- I CHARACTERISTIC W/O PRESSURE COMPENSATION
ECV85D2 Current/Pressure Characteristic
6.0
5.0
Bar
4.0
3.0
2.0
1.0
0.0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
Amp
FIG. 6 – CLOSED LOOP STANDARD P- I CHARACTERISTIC WITH PRESSURE COMPENSATION
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ECV85D2 (Directly Proportional Electro-hydraulic Converter)
Product Guide
!"
FIG. 7 – Modulated oil pressure versus flow with no drive current
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Product Guide
ABB Business Unit Power Generation
Via Hermada, 6
16154 Genova
NOTE:
ITALY
We reserve the right to make technical changes or modify the contents
of this document without prior notice. With regard to purchase orders,
the agreed particulars shall prevail. ABB does not accept any
responsibility whatsoever for potential errors or possible lack of
information in this document.
Phone: +39 (0) 10 607.3351
Fax:
+39 (0) 10 607.3533
E-mail: [email protected]
Internet: http://www.abb.com/powergeneration
We reserve all rights in this document and in the subject matter and
illustrations contained therein. Any reproduction - in whole or in parts is forbidden without ABB'
s prior written consent.
Copyright© 2005 ABB
All rights reserved.
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ECV85D2– Product Guide
ECV85D2 (Directly Proportional Electro-hydraulic Converter)