AUTOMATIC TRANSFER SWITCHES

1
(No Transcript)
2
Transfer/Bypass Isolation Switch - General Review
3
Introduction
This presentation will provide you with an
overview of Russelectric Transfer/Bypass
Isolation Switches.
r
4
Definition

• A manually operated device used in conjunction
  with a transfer switch to provide a means of
  directly connecting load conductors to a power
  source and of disconnecting the transfer switch.

r
5
Applications

• No Break/Overlapping Design Where a bypass
  isolation switch is required but where
  maintenance or testing without disturbing the
  load is a priority
• Load Break Design Where a bypass isolation
  switch is required and simplicity of operation is
  critical during an emergency condition

6
Views of the Bypass Switch
Conduit Entry
Bypass/Isolation Handles
Load Connection
Normal Connection
Emergency Connection
Transfer Switch
r
Conduit Entry
7
Views of the Bypass Switch
Eyebolts for lifting
Shifter Handle Plate
Bypass/Isolation Portion
Microprocessor and Accessory Plate
Transfer Switch Portion
r
8
Views of the Bypass Switch
r
9
Views of the Bypass Switch
r
10
Views of the Bypass Switch
r
11
No Break Bypass
There is no interruption in power to a critical
load during bypass operations. During the
bypass operation, the automatic switch and the
non-automatic switch are paralleled on the same
source.
r
12
No Break - Normal
With the Isolating Handle in the Normal Position,
the Automatic Transfer Switch is feeding the Load
with the available source. In this case, it is
the Normal Source. If Normal is lost, the
Transfer Switch will
13
No Break - Emergency
transfer to the Emergency Source.
14
No Break - Normal
In this position, the Load is being fed by the
Normal Source through the Transfer Switch.
15
No Break Bypass Normal
When the Bypass Handle is moved to Bypass to
Normal, the Normal Bypass Contact closes
(Makes). At this point, the Load is being fed by
the Normal source through both the Bypass Switch
and the Transfer Switch.
16
No Break Bypass Normal
The Load Break Contact opens (breaks) and the
Load is being fed by the Normal Source through
the Bypass Switch. Power is still on the
Transfer Switch, however, the open Load Break
Contact is preventing the Transfer Switch from
feeding the Load.
17
No Break Bypassed Normal (Isolated)
Moving the Isolating Handle to the the Isolate
Position disconnects the Transfer Switch from the
circuit. There is no power on the Transfer
Switch. The Load is being fed by the Normal
Source.
18
No Break Bypassed Emergency (Isolated)
If the Emergency Source is available, it is
possible to transfer the Bypass Switch to the
Emergency Source while the Transfer Switch is
isolated.
19
No Break Bypassed Emergency
Moving the Bypass Handle to Bypass to Emergency
opens the Normal Bypass Switch Contacts
20
No Break Bypassed Emergency (Isolated)
and closes the Emergency Bypass Switch Contacts.
21
No Break Bypassed Emergency
Moving the Isolating Handle back to the Normal
Position racks the Transfer Switch back into the
circuit. At this point, the Load is still fed by
the Emergency Source through the Bypass Switch.
Notice that the transfer switch is in a different
position than the Bypass Switch. This is not a
problem because of the Load Break Contact.
22
No Break Bypassed Emergency
Moving the Isolating Handle back to the Normal
Position racks the Transfer Switch back into the
circuit. At this point, the Load is still fed by
the Emergency Source through the Bypass Switch.
Notice that the Transfer Switch is in the same
position as the Bypass Switch. Our No Break
design will not allow you to rack the Transfer
Switch back in unless it is in the same position
as the Bypass Switch. The Load is still fed
through the Bypass Switch because the Load Break
Contact is still open.
23
No Break - Emergency
When the Bypass Handle is moved to Auto, the Load
Break Contact closes (makes). The Load is now
fed by the Emergency Source through the Automatic
Transfer Switch and the Bypass Switch.
24
No Break - Emergency
The Bypass Switch Contacts open (break) and the
Load is being fed through only the Transfer
Switch.
25
Benefits of the RTB(D)NB - No Break Design

• Power can be maintained to load during ATS
  failure
• Provides for a means of bypassing the ATS without
  interrupting power to the load for maintenance
  and ATS testing
• The speed of the contacts is independent of the
  speed of the bypass handle movement

r
26
Features of the RTB(D)NB - No Break Design

• The load break contact (see one-line)
• Contacts and Over-Center Mechanism is identical
  to the ATS
• The contact speed is independent of the speed of
  the bypass handle movement
• A simple electro-mechanical interlock system
  activated by a single push-button

r
27
Operation - RTB(D)NB - No Break Design

• 1. Observe - the ATS position
• 2. Slide - the handle to the ATS source
  position
• 3. Push - the solenoid interlock push-
  button
• 4. Pull - the bypass handle down
• 5. Pull - isolating handle to isolate ATS

r
28
Load Break Bypass
A load break contact opens during the bypass
operation to allow bypass to either source. The
load is interrupted during the bypass operation.
r
29
Load Break - Normal
With the Isolating Handle in the Normal Position,
the Automatic Transfer Switch is feeding the Load
with the available source. In this case, it is
the Normal Source. If Normal is lost, the
Transfer Switch will
30
Load Break - Emergency
transfer to the Emergency Source.
31
Load Break - Normal
In this position, the Load is being fed by the
Normal Source through the Transfer Switch.
32
Load Break Bypass Normal
When the Bypass Handle is moved to Bypass to
Normal, the Load Break Contact opens. At this
point, the Load is not being fed by either source.
33
Load Break Bypass Normal
The Normal Bypass Switch Contacts close and the
Load is being fed by the Normal Source. Power is
still on the Transfer Switch, however, the open
Load Break Contact is preventing the Transfer
Switch from feeding the Load.
34
Load Break Bypassed Normal (Isolated)
Moving the Isolating Handle to the the Isolate
Position disconnects the Transfer Switch from the
circuit. There is no power on the Transfer
Switch. The Load is being fed by the Normal
Source.
35
Load Break Bypassed Emergency (Isolated)
If the Emergency Source is available, it is
possible to transfer the Bypass Switch to the
Emergency Source while the Transfer Switch is
isolated.
36
Load Break Bypassed Emergency
Moving the Bypass Handle to Bypass to Emergency
opens the Normal Bypass Switch Contacts
37
Load Break Bypassed Emergency (Isolated)
and closes the Emergency Bypass Switch Contacts.
38
Load Break Bypassed Emergency
Moving the Isolating Handle back to the Normal
Position racks the Transfer Switch back into the
circuit. At this point, the Load is still fed by
the Emergency Source through the Bypass Switch.
Notice that the transfer switch is in a different
position than the Bypass Switch. This is not a
problem because of the Load Break Contact.
39
Load Break Bypassed Emergency
The Transfer Switch automatically transfers to
the Emergency Source. The Load is still fed
through the Bypass Switch because the Load Break
Contact is still open.
40
Load Break - Emergency
When the Bypass Handle is moved to Auto, the
Emergency Bypass Switch Contacts open and the
Load Break Contact closes (there is a point where
both the Emergency Bypass Switch Contacts and the
Load Break Contact is open). The Load is now fed
by the Emergency Source through the Automatic
Transfer Switch.
41
Failure Scenarios
The next few slides will demonstrate the
advantages of the Load Break Bypass design in
several possible failure scenarios.
r
42
Load Break Bypass Normal
The switch is bypassed to the normal source
43
Load Break Bypass Normal Lose Normal
When the normal source is lost.
44
Load Break Bypass Normal Engine Start
An engine start signal is sent and the emergency
source becomes available.
45
Load Break Bypassed Emergency
By simply moving the bypass handle to the BYPASS
TO EMERGENCY position, the load is supplied by
the emergency source.
46
Load Break - Normal
The load is being supplied by the normal source
through the transfer switch...
47
Load Break Normal Lose Normal
When the normal source is lost.
48
Load Break Normal Engine Start
An engine start signal is sent and the emergency
source becomes available. However, a problem
with the transfer switch prevents transfer to the
emergency source.
49
Load Break Bypassed Emergency
By simply moving the bypass handle to the BYPASS
TO EMERGENCY position, the load is supplied by
the emergency source.
50
Benefits of the RTB(D) - Load Break Design

• Power can be maintained to load during ATS
  failure
• Provides a means of bypassing the ATS for
  maintenance
• No elaborate system of electrical solenoids,
  electrical interlocks or mechanical interlocks
• Fast, Simple and Easy Operation

r
51
Features of the RTB(D) - Load Break Design

• Utilizes an absolute foolproof method of
  bypassing to either normal or emergency
• The load break contact (see one-line)
• Contacts and Over-Center Mechanism are identical
  to the ATS
• The contact speed is independent of the speed of
  the bypass handle movement

r
52
Operation - RTB(D) - Load Break Design

• 1. Observe - that the source is available
• 2. Slide - the handle over to the
  desired/available source
• 3. Pull - the bypass handle down
• 4. Pull - isolating handle to isolate ATS

R
53
1. Observe - that the source is available
R
54
2. Slide - the handle over to the
desired/available source
and 3. Pull - the bypass handle down
R
55
4. Pull - isolating handle to isolate ATS
R
56
Rack-out - Remove ATS if desired
R
57
If Normal Source is lost while Isolated or Racked
out - Engine start signal will automatically be
given. When Emergency source is available,
bypass to Emergency
R
58
Slide Bypass Handle over to Emergency
R
59
Slide Bypass Handle over to Emergency
R
60
Access - 100 through 3000 Amp

• Standard Rear or Both Sides
• Front Access Only
• Top Transition Pull Box
• Side Transition Cubicle (Left or Right)

r
61
Access - 4000 Amp

• Available in Rear Access Only

r
62
Power Connections

• EDS 185 - RMT/RTB Lug Data Sheet
• Compression and Provisions For
• Bus Duct Connections

r
63
Construction Features

• 12-gauge steel enclosure
• Plenty of cable bending space
• No aluminum bus or components

• Bus connections - Belleville type compression
  washers
• 90 degree Celsius rated Lugs
• Self-aligning ATS draw-out
• Maintain Engine Start on Bypass to Emergency

R
64
Ratings3-Cycle Close and Withstand

• 100 - 400 Ampere 42,000 Amps
• 600 - 800 Ampere 65,000 Amps
• 1000 - 1200 Ampere 85,000 Amps
• 1600 - 4000 Ampere 100,000 Amps

R
65
r