S= inlet (suction port)
P= outlet (pressure port)
R1 (ME5) =oil return from relief and
R2 (MFE5) pressure limiting valve
1) Ports tapped for solderless 8 mm diam tube connection.
Explanation of hydraulic function
Both types have the same hydraulic function.
Oil is sucked in at Sand flows under pressure through the duct in the
direction P. The oil pressure closes valve Vand opens valve E3, at the
same time closing valve E1 against spring tension. If air is entrained
(due to low oil level in the reservoir),valve Vremains open and diverts
the air or, respectively, the air-oil mixture into the return duct (see
bubble (o) marking in direction R1). Valve Callows oil under overpres-
sure to flow out into the return duct (see cross (+) marking).
When the unit stops (interval time), spring-loaded valve E1 opens and
valve E3 simultaneously closes. The system pressure at Pcan now
be released through valve E1 – with the exception of asmall amount
of residual pressure determined by valve E2. This pressure release is
required for the piston distributors to function correctly.
The pressure relief process is shown in Fig. 4.
Explanation of the structural differences
In the case of model ME5, the long screw plug D1 blocks flangedport
R2 of the return duct. The oil returning from valves V, Cand E1 flows
via port R1 through a tube to the separately mounted oil reservoir
(see Fig. 1 and 2).
In the case of model MFE5, the short screw plug D2 – unlike D1 with
model ME5 – leaves flanged port R2 open. A plug closes off external
port R1. – Flanged port R2 of the return duct drains directly into the
reservoir without any connection threads (see Fig. 3 and 4).
Technical data of the shown motor
Motor . . . . . . . . . . . . . . . . Three-phase motor
Mode of operation . . . . . . . . . . S1, 100%
Insulation class . . . . . . . . . . . . F
Rated frequency [Hz] . . . . . . . . . 50 60
Voltage [V] Y 4). . . . . . . . . . . . 400 480
Rated current [A] . . . . . . . . . . . 0.29 0.29
Rated power [kW] . . . . . . . . . . 0.075 0.09
Rated speed [rpm] . . . . . . . . . . 2700 3200
Rated flow rate [l/min] . . . . . . . . 0.5 0,.6
Operating pressure [bars] . . . . . . . 28
Operating temperature [°C] . . . . . +10 to +40
Medium . . . . . . . . . . . . . . . 20 to 1000 mm2/s
Type of enclosure acc. to DIN 50050 . IP 54
Max. suction head [mm] . . . . . . . 500
4) See page 6: “Multivoltage motors”
MFE5 unit variants *
Flow Max. back
rate 2)pressure
3)
Order No. [l/min] [bars] Design
MFE5-2000 0.5 28 Basic version, NBR,
plastic terminal box
MFE5-3041 0.5 28 Basic version, NBR,
metal terminal box
MFE5-2000-D 0.5 28 Installed below oil level,
NBR, plastic terminal box
MFE5-3000-D 0.5 28 Installed below oil level,
NBR, metal terminal box
MFE5-2008 0.5 28 Basic version, FKM (FPM),
plastic terminal box
MFE5-2009 0.25 17.5 For light oil as of 5 mm2/s, NBR
MFE5-2053 0.25 17.5 For light oil as of 5 mm2/s, FKM
MFE5-4000 0.5 28 UL/CSA-approved, NBR
MFE5-5000 0.5 28 CCC-approved, NBR
MFE5-1001 0.5 28 HAN6ES Harting connector, NBR,
Motor 180° turned
MFE5-1088 0.5 28 HAN10ES Harting connector, FKM
MFE5-S67 0.5 28 50/95 weatherproofing, NBR,
metal terminal box
*) The geometrical dimensions of the variants can deviate of Fig. 5.
2) Flow rate based on an operating viscosity of 140 mm2/s,
at a back pressure of p = 5 bars.
3) The max. back pressure is equivalent to the actual value of the built-in pressure
limiting valve. If the units are operated with a single-phase AC supply, only 60% of
the indicated pressure is permissible, i.e. a 16-bar pressure limiting valve should be
fitted to the system.
The appropriate capacitors for a frequency of 50 and 60 Hz are:
230 V ... 8 μF: order No. 179-340-007
115 V ... 30 μF: order No. 179-340-060
Fig. 5
