EV-Switch tm / TFI-1xx Automatic 240VAC Switch
A. DESCRIPTION:
The EV-Switch tm / TFI-1xx AC Switch Box (EVSTASB) is a patented and intelligent microcomputer-based AC switch that enables automatic time-sharing of an existing 220-240VAC outlet for two or more AC loads.
The EVSTASB consists of a NEMA plug cable connection to a 220-240VAC wall outlet, 2 NEMA receptacles: one for dryer, the other for EV charging port, and an optional AC volt-amp-watt meter.
TFI AC Switch Set-up Examples.
The AC meter provides Volts, Amp, Watt measurements (1% accuracy) on the EV side and thus adds convenience and safety enhancement to the system but it is not required for normal system operation.
The user just taps on SEL to scroll through the measurements. Press and hold SEL for three seconds for automatic scrolling of the measurements. Tap SEL again to return to manual scrolling mode.
After 60 seconds in a particular measurement, the AC meter will remember the setting and will power up to that setting after power cycling.
The patented design approach results in the thinnest/smallest housing/box.
Since only one AC load is allowed at any given time, the load time-sharing scheme offers a safe and economical way to use an existing 220-240VAC outlet that is typically already connected to an electric dryer for multiple AC loads while eliminating the need to upgrade the electrical panel/circuit breaker box [in a house with a 100A electric panel] to safely install additional 220-240VAC outlet(s) for an EVSE (EV supply equipment) Level 2.
Alternately, load time-sharing may also minimize any upgrade cost by allowing the homeowner to only upgrade minimally (for example, a house with a gas dryer can just add a low-cost 240VAC outlet), then use the 240VAC outlet time-sharing approach to charge several electric vehicles in one session.
A typical usage is to time-share an electric dryer and an electric vehicle (EV) charging port. But when the electric dryer is not used, the TFI-1xx can be used to to time-share the charging of two electric vehicles (EV).
Two EVSTASBs in cascade/series, either 2x EV-Switch tm / TFI-1xx or 1x EV-Switch tm / TFI-2xx + 1xTFI-1xx, will enable the time-sharing of 3x AC loads, e.g.,1x dryer and 2 EV charging ports. This ability to charge more than one EV in one charging session can be especially beneficial to owners of multiple lower-cost EVs with shorter driving range that need frequent charging for daily use.
To cascade, plug the cable of next unit into the EV side of the current unit etc.
In general, n (n>=1) units in cascade will support n+1 electric devices / AC loads.
When load time-sharing with an electric dryer, the 1st unit in the cascade can be either a EV-Switch tm / TFI-2xx or a EV-Switch tm / TFI-1xx but subsequent units need to be the intelligent EV-Switch tm / TFI-1xx. The user is free to make any AC load connection and charging set-up. The TFI-1xx will prevent any conflict from becoming an overload condition. For conflict-free operation, the user simply schedules the use of one connection before the other. In case of a scheduling conflict, the Dr port has higher priority and will be serviced before the EV port.
See example at : TFI AC Switch Set-up Examples.
Standard models :
Notes : NEMA 10-30R = 3-prong receptacle, 30A pre-1996 240VAC outletNEMA 14-30R = 4-prong receptacle, 30A after-1996 240VAC outlet
EV-Switch tm / TFI-10 : Automatic 240VAC Switch (generic NEMA 10-30R 3-prong -- NO AC Meter)
EV-Switch tm / TFI-10B : Automatic 240VAC Switch (industrial-grade (Bryant) NEMA 10-30R 3-prong -- NO AC Meter)
EV-Switch tm / TFI-10H : Automatic 240VAC Switch (industrial-grade (Hubbell) NEMA 10-30R 3-prong -- NO AC Meter)
EV-Switch tm / TFI-100 : Automatic 240VAC Switch (generic NEMA 10-30R 3-prong receptacles + AC Meter)
EV-Switch tm / TFI-100B : Automatic 240VAC Switch (industrial-grade (Bryant) NEMA 10-30R 3-prong receptacles + AC Meter)
EV-Switch tm / TFI-100H : Automatic 240VAC Switch (industrial-grade (Hubbell) NEMA 10-30R 3-prong receptacles + AC Meter)
EV-Switch tm / TFI-14 : Automatic 240VAC Switch (generic NEMA 14-30R 4-prong -- NO AC Meter)
EV-Switch tm / TFI-14B : Automatic 240VAC Switch (industrial-grade (Bryant) NEMA 14-30R 4-prong -- NO AC Meter)
EV-Switch tm / TFI-14H : Automatic 240VAC Switch (industrial-grade (Hubbell) NEMA 14-30R 4-prong -- NO AC Meter)
EV-Switch tm / TFI-104 : Automatic 240VAC Switch (generic NEMA 14-30R 4-prong + AC Meter)
EV-Switch tm / TFI-104B : Automatic 240VAC Switch (industrial-grade (Bryant) NEMA 14-30R 4-prong + AC Meter)
EV-Switch tm / TFI-104H : Automatic 240VAC Switch (industrial-grade (Hubbell) NEMA 14-30R 4-prong + AC Meter)
Customized models : EV-Switch tm / TFI-100F (10-30R 3-prong, 24A, 50C/55C) ; EV-Switch tm / TFI-104FH (14-30R 4-prong, 24A, 50C/55C).
All EV-Switch tm / TFI-1xx models can be ordered with option S which provides the extra safety protection by limiting the EV charging current to 27A (+/- 5%). (Note that certain charging devices such as Tesla Mobile Units with NEMA 10-30P already limit the limit charging current to 24A maximum thus they do not need this option).
B. OPERATION:The EVSTASB includes a fast microcomputer that constantly and accurately monitors the AC input at the higher priority port (i.e., dryer side) to determine if it is active or not.
If/when the dryer is not active, the other port (EV side) is connected to the AC source. The AC meter (if used) or an EV LED is ON to indicate AC connection. The Dryer LED is OFF.
If/when the dryer side is active, the AC connection at the EV side is instantly removed. The Dryer LED is ON to indicate AC connection. The AC meter (if used) or EV LED is OFF.
The AC connection at the EV side will automatically return after the dryer side is inactive for more than ~120 seconds* (~2 minutes). The AC switching is done automatically by the microcomputer.
*(Note that this 120-second delay enables the User to check the dryer 's laundry load then decide to continue drying operation or not without prematurely turning on the EV port. This is particularly helpful in case the EV charging electronics may declare a fault condition after several AC input interruptions).
Typically, the User connects the EVSTASB to the existing 240VAC outlet, a dryer to Dr side, and an EV charging device to EV side then proceeds to use the dryer and EV charging port normally. The User should make sure all the NEMA plugs fit snugly and completely into the receptacles without any visible gap between them.
Alternately, when the dryer is not used, the two ports (Dr and EV) can be time-shared to charge two EVs one at a time.
The standard EV-Switch tm /TFI-1xx product is good for 24A load at up to 40C (104F) ambient temperature. When the ambient temperature is less than 40C (104F), the system can support more than 24A load without thermal interruption.
C. SAFETY FEATURES :To minimize risks to the User and their property, the EVSTASB has the following safety features :
i. Fast and safe switching of the dryer and EV AC loads with NO [appreciable] over-lapping currents.
ii. Flashing/strobing LED : An LED is used to report the status of the dryer port. The Hi/On state indicates the dryer port is active. The Lo/Off state means the dryer port is inactive. Additionally, the LED state is momentarily reversed for ~ 0.5 seconds (twice in Off state, once in On state) by the control software every ~ 3 seconds. This "complex" strobing pattern is an indication to the User that the microcomputer is running normally and is in full control of the AC switching. Note that the chance of the microcomputer failing is very small but this visual indicator can help the User take proper action to prevent a potential fire hazard.
If/when such LED strobing/flashing is absent, then either the LED or the microcomputer is not functioning. Since a strobing LED has very high MTBF (Mean Time Between Failure) and is less likely to fail than the microcomputer, it is advisable that the EVSTASB be proactively removed from service and the factory contacted.
iii. The EVSTASB will remove AC to the EV side when the internal (i.e., inside the box) temperature is higher than ~73 C +/- 2C to preclude overheating. This may happen when there is an excessively large current or when the outside/ambient temperature is consistently higher than ~40C (~104F). (~50/55 C or ~122/131 F for model TFI-10xF).
The LED will continually flash on/off at the ~0.5 sec rate during the thermal shut-down period.
Automatic AC re-connection occurs after the cool-off time of ~60 minutes.
iv. Additionally, for any charging unit that may allow more than 24A, the TASB offers the option S to monitor and safely remove AC connection to the EV side when the charging current is higher than 27A (90% of outlet 30A rating) +/- 5% to protect itself and the house 30A circuit breaker.
Note that certain EV charging circuits, e.g., Tesla Mobile Unit with NEMA 10-30P, already have the safety feature that limits the charging current to 24A (80% of 30A circuit breaker rating) thus they do not need this option S.
The LED will continually flash on/off at the ~0.5 sec rate during this over-current shut-down period.
Automatic AC re-connection occurs after ~2 minutes.
v. An external fuse is used to protect against any short circuit in the AC volt-amp-watt meter.
D. TECHNICAL SPECIFICATIONS:
1. Mechanical :
1.1 Dimensions :
Models EV-Switch tm / TFI-10xx, TFI-100xx :
6.3 in x 6.3 in x 2.36 in (160 mm x 160 mm x 60 mm)
Models EV-Switch tm / TFI-14xx, TFI-104xx :
6.3 in x 6.3 in x 3.54 in (160 mm x 160 mm x 90 mm)
1.2 Material : ABS or polycarbonate plastic
1.3 Weight : EV-Switch tm / TFI -10x ~3.5 lbs ; TFI-14x , TFI-104x ~5 lbs
2. Electrical : 220 -240 VAC ; up to 30 A -- safe limit : 24 A (30A outlet)
2.1 AC meter fuse : 250VAC @ 0.5A -- PN 0216.500HXP or equivalent
2.2 Power consumption (typ., PF ~= 0) with no load : Dr mode ~ 1W ; Ev mode ~ 1.5W with AC meter
3. Operating Ambient Temperature Range And Environmental Conditions :
Standard product: @ 24A load (30A outlet)
3.1 Model TFI-10xx : 0 C to 40 C (32 F to 104 F) +/- 1C (1.8F) in EV mode.
(With AC meter) 0 C to 45 C (32 F to 113 F) +/- 1C (1.8F) in Dr mode.
Model TFI-1xx : -20 C to 40 C (-4 F to 104 F) +/- 2C (1.8F) in EV mode.
(NO AC meter) -20 C to 45 C (-4 F to 113 F) +/- 2C (1.8F) in Dr mode.
Customized product: @ 24A load (30A outlet)
3.2 Model TFI-10xF : 0 C to 45 C (32 F to 113 F) +/- 1C (1.8F) in EV mode.
(With AC meter) 0 C to 50 C (32 F to 122 F) +/- 1C (1.8F) in Dr mode.
Model TFI-1xxF: -40 C to 45 C (-40 F to 113 F) +/- 1C (1.8F) in EV mode.
(NO AC meter) -40 C to 50 C (-40 F to 122 F) +/- 1C (1.8F) in Dr mode.
3.3 Humidity (non-condensing) : 20 to 85%
3.4 Indoor use only -- Not liquid resistant4. The EVSTASB may be further customized to allow operation at :
4.1 Up to 50 C (122 F) ambient temperature at 24A load
4.2 To -40 C (-40 F) ambient temperature at 27A to 30A load
Please contact factory for customized products.
E. SAFETY WARNING :
240VAC can be lethal and/or a fire hazard !Working with it requires specialized knowledge.
DO NOT ATTEMPT TO OPEN THE BOX OR REPAIR IT !Contact factory for service.
F. MAINTENANCE :
There is no need for any regular maintenance other than to keep the unit free of dust, dirt and grease. Wearing protective gloves, the user can use a dry soft cloth to lightly wipe off any dust or dirt (when necessary).
Avoid any liquid spill. (Liquid spill is not covered by warranty).
In case of accidental liquid spillage, the user should first wear protective gloves then remove power from the unit and contact factory for service.
G. MISC : Designed and manufactured in the USA using USA and Japanese technologies.